Buggy python submission (verdict: Runtime Error):
H, W, M = map(int, input().split())
boms = set()
Hs = [0] * H
Ws = [0] * W
for i in range(M):
  h, w = map(lambda x: int(x) - 1, input().split())
  boms.add((h, w))
  Hs[h] += 1
  Ws[w] += 1
  
Hmax = max(Hs)
HMaxIndexs = set()
for i, h in enumerate(Hs):
  if h == Hmax:
    HMaxIndexs.add(i)

Wmax = max(Ws)
WMaxIndexs = set()
for i, w in enumerate(Ws):
  if w == Wmax:
    WMaxIndexs.add(i)

count = 0
for bom in boms:
  if (bom[0] in HMaxIndexs) and (bom[1] in WMaxIndexs):
    count += 1
print(Hmax + Wmax - 1) if count == len(HMaxIndexs) * len(WMaxIndexs) else print(Hmax + Wmax)



Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
t = [list(input()) for _ in range(h)]
d = deque([(Ch, Cw)])
d2 = deque()
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = range(-2, 3)

while True:
  # 移動A
  while len(d) != 0:
    Th, Tw = d.popleft()
    d2.append((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  while len(d2) != 0:
    Th, Tw = d2.popleft()
    for i in b :
      for j in b :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
          visited[Th][Tw] = 1
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
t = [list(input()) for _ in range(h)]
d = deque([(Ch, Cw)])
d2 = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = range(-2, 3)

while True:
  # 移動A
  while len(d) != 0:
    Th, Tw = d.popleft()
    d2.append((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  while len(d2) != 0:
    Th, Tw = d2.popleft()
    for i in b :
      for j in b :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
          visited[Th][Tw] = 1
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0 and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = ((1,0),(-1,0),(0,1),(0,-1))

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = []
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.append((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and visited[_h][_w] == 0 and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])  # 陸路で行くところ
d2 = deque([(Ch, Cw)]) # 直前のワープ後に陸路でいった場所のメモ
s = set() # いったところ
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  while len(d) != 0:
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    d2.append((Th, Tw))
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if _p == (Dh, Dw):
        print(ans)
        exit()
      if not _p in s and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  while len(d2) != 0:
    Th, Tw = d2.popleft()
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if _p == (Dh, Dw):
          print(ans)
          exit()
        if not _p in s and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
d2 = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  while len(d) != 0:
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    d2.append((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if not _p in s and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  while len(d2) != 0:
    Th, Tw = d2.popleft()
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if not _p in s and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
d2 = deque()
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  while len(d) != 0:
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    d2.append((Th,Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if not _p in s and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  while len(d2) != 0:
    Th, Tw = d2.popleft()
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if not _p in s and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if not _p in s and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if not _p in s and 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if (not (_p) in s) and 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in s) and 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.' and (not (_p) in d):
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.' and (not (_p) in d):
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while d != deque():
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if (not (_p) in s) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2, -1, 0, 1, 2]

while True:
  # 移動A
  stemp = set()
  while d != deque():
    Th, Tw = d.popleft()
    s.add((Th, Tw))
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h = Th + i
      _w = Tw + j
      _p = (_h, _w)
      if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
        d.append(_p)
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in b:
      for j in b:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

news = set()
news.add((Ch, Cw))
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2,-1,0,1,2]
while True:
  # 行けるところすべて追加
  targets = set()
  while len(news) > 0:
    olds = set(news)
    targets |= olds
    news = set()
    for Th, Tw in olds:
      for i,j in a:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if not (_p) in s and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          news.add(_p)
          s.add((Th,Tw))
  # クリアしてるか確認
  if (Dh,Dw) in targets:
    print(ans)
    exit()
  else:
    news = set()
    ans += 1
    for Th,Tw in targets:
      for i in b:
        for j in b:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          if not (_p) in s and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            news.add(_p)
            s.add((Th,Tw))
    if len(news) == 0:
      print('-1')
      exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d1 = deque()
d.append((Ch, Cw))
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2,-1,0,1,2]
while True:
  # 行けるところすべて追加
  targets = set()
  while len(d) > 0:
    temps = set(d)
    targets |= temps
    d = deque()
    for Th, Tw in temps:
      for i,j in a:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          s.add((Th,Tw))
  # クリアしてるか確認
  if (Dh,Dw) in targets:
    print(ans)
    exit()
  else:
    d = deque()
    ans += 1
    for Th,Tw in targets:
      for i in b:
        for j in b:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
            s.add((Th,Tw))
    if len(d) == 0:
      print('-1')
      exit()


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d1 = deque()
d.append((Ch, Cw))
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1)]
b = [-2,-1,0,1,2]
while True:
  # 行けるところすべて追加
  targets = set()
  while len(d) > 0:
    temps = set(d)
    targets |= temps
    d = deque()
    for Th, Tw in temps:
      for i,j in a:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in s) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          s.add((Th,Tw))
  # クリアしてるか確認
  if (Dh,Dw) in targets:
    print(ans)
    exit()
  else:
    s |= targets
    d = deque()
    for Th,Tw in targets:
      for i in b:
        for j in b:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          if (not (_p) in s) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Runtime Error):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d.append((Ch, Cw))
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1),(0,0)]
b = [-2,-1,0,1,2]
while True:
  flag = True
  # 行けるところすべて追加
  while flag:
    flag = False
    for _ in range(len(d)):
      Th, Tw = d.popleft()
      for i,j in a:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (Dh,Dw) == _p:
          print(ans)
          exit()
        if (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          if not(i == 0 and j == 0):
            flag = True
  # クリアしてるか確認
  temps = set(d)
  else:
    s |= temps
    d = deque()
    for Th,Tw in temps:
      for i in b:
        for j in b:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          if (not (_p) in s) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d.append((Ch, Cw))
ans = 0
s = set() # いったところ
a = [(1,0),(-1,0),(0,1),(0,-1),(0,0)]
b = [-2,-1,0,1,2]
while True:
  flag = True
  # 行けるところすべて追加
  while flag:
    flag = False
    for _ in range(len(d)):
      Th, Tw = d.popleft()
      for i,j in a:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          if not(i == 0 and j == 0):
            flag = True
  # クリアしてるか確認
  temps = set(d)
  if (Dh,Dw) in temps:
    print(ans)
    exit()
  else:
    s |= temps
    d = deque()
    for Th,Tw in temps:
      for i in b:
        for j in b:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          if (not (_p) in s) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d.append((Ch, Cw))
ans = 0
s = set() # いったところ

while True:
  flag = True
  # 行けるところすべて追加
  while flag:
    flag = False
    for _ in range(len(d)):
      Th, Tw = d.popleft()
      for i,j in [(1,0),(-1,0),(0,1),(0,-1),(0,0)]:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        if (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          if not(i == 0 and j == 0):
            flag = True
  # クリアしてるか確認
  temps = set(d)
  if (Dh,Dw) in temps:
    print(ans)
    exit()
  else:
    s |= temps
    d = deque()
    for Th,Tw in temps:
      for i in [-2,-1,0,1,2]:
        for j in [-2,-1,0,1,2]:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          if (not (_p) in s) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1


Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d.append((Ch, Cw))
flag = True
ans = 0
s = set()

while True:
  while flag:
    flag = False
    for _ in range(len(d)):
      Th, Tw = d.popleft()
      for i,j in [(1,0),(-1,0),(0,1),(0,-1),(0,0)]:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        temp = (Th + i, Tw + i)
        if (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          # print(_p)
          if not(i == 0 and j == 0):
            flag = True
  if (Dh,Dw) in d:
    print(ans)
    exit()
  else:
    s |= set(d)
    temps = set(d)
    d = deque()
    for Th,Tw in temps:
      for i in [-2,-1,0,1,2]:
        for j in [-2,-1,0,1,2]:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          temp = (Th + i, Tw + i)
          if (not (_p) in temps) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d.append((Ch, Cw))
flag = True
ans = 0
s = set()

while True:
  while flag:
    flag = False
    for _ in range(len(d)):
      Th, Tw = d.popleft()
      for i,j in [(1,0),(-1,0),(0,1),(0,-1),(0,0)]:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        temp = (Th + i, Tw + i)
        if (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          # print(_p)
          if not(i == 0 and j == 0):
            flag = True
  if (Dh,Dw) in d:
    print(ans)
    exit()
  else:
    s |= set(d)
    temps = set(d)
    d = deque()
    for Th,Tw in s:
      for i in [-2,-1,0,1,2]:
        for j in [-2,-1,0,1,2]:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          temp = (Th + i, Tw + i)
          if (not (_p) in temps) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d.append((Ch, Cw))
flag = True
ans = 0

while True:
  while flag:
    flag = False
    for _ in range(len(d)):
      Th, Tw = d.popleft()
      for i,j in [(1,0),(-1,0),(0,1),(0,-1),(0,0)]:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        temp = (Th + i, Tw + i)
        if (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          # print(_p)
          if not(i == 0 and j == 0):
            flag = True
  if (Dh,Dw) in d:
    print(ans)
    exit()
  else:
    l = set(d)
    d = deque()
    for Th,Tw in l:
      for i in [-2,-1,0,1,2]:
        for j in [-2,-1,0,1,2]:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          temp = (Th + i, Tw + i)
          if (not (_p) in l) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque()
d.append((Ch, Cw))
flag = True
ans = 0

while True:
  while flag:
    flag = False
    for _ in range(len(d)):
      Th, Tw = d.popleft()
      for i,j in [(1,0),(-1,0),(0,1),(0,-1),(0,0)]:
        _h = Th + i
        _w = Tw + j
        _p = (_h, _w)
        temp = (Th + i, Tw + i)
        if (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
          d.append(_p)
          # print(_p)
          if not(i == 0 and j == 0):
            flag = True
  if (Dh,Dw) in d:
    print(ans)
    exit()
  else:
    l = list(d)
    d = deque()
    for Th,Tw in l:
      for i in [-2,-1,0,1,2]:
        for j in [-2,-1,0,1,2]:
          _h = Th + i
          _w = Tw + j
          _p = (_h, _w)
          temp = (Th + i, Tw + i)
          if (not (_p) in l) and (not (_p) in d) and _h >= 0 and _h < h and _w >= 0 and _w < w and t[_h][_w] == '.':
            d.append(_p)
    if len(d) == 0:
      print('-1')
      exit()
    ans += 1

Fixed submission:
from collections import deque

h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
Ch -= 1
Cw -= 1
Dh -= 1
Dw -= 1
t = [[i for i in range(w)] for j in range(h)]
visited = [[0 for i in range(w)] for j in range(h)] # いったところ
ans = 0
for i in range(h):
  temp = input()
  for j in range(w):
    t[i][j] = temp[j]

d = deque([(Ch, Cw)])
ans = 0
a = [(1,0),(-1,0),(0,1),(0,-1)]

while True:
  # 移動A
  stemp = set()
  while len(d) != 0:
    Th, Tw = d.popleft()
    # s.add((Th, Tw))
    visited[Th][Tw] = 1
    stemp.add((Th, Tw))
    if (Th,Tw) == (Dh, Dw):
      print(ans)
      exit()
    for i, j in a:
      _h,_w = Th + i, Tw + j
      _p = (_h, _w)
      if 0 <= _h < h and 0 <= _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
        d.append(_p)
        visited[_h][_w] = 1
  # 移動B
  ans += 1
  for Th,Tw in stemp:
    for i in range(-2, 3) :
      for j in range(-2, 3) :
        _h,_w = Th + i, Tw + j
        _p = (_h, _w)
        if 0 <= _h < h and 0 <=  _w < w and t[_h][_w] == '.' and visited[_h][_w] == 0:
          d.append(_p)
  if len(d) == 0:
    print('-1')
    exit()