Buggy python submission (verdict: Time Limit Exceeded):
import sys
reader = (s.rstrip() for s in sys.stdin)
input = reader.__next__

h,w = map(int, input().split())
ch,cw = map(int, input().split())
ch,cw = ch-1, cw-1
dh,dw = map(int, input().split())
dh,dw = dh-1,dw-1
s = [list(map(lambda x: x==".", input())) for i in range(h)]

inf = 2**32-1
count = [[inf]*w for i in range(h)]

from collections import deque
que = deque()
que.append((ch,cw,0))

dxdy = [(0,1),(1,0),(0,-1),(-1,0)]

while que:
    x,y,c = que.pop()
    if count[x][y] <= c:
        continue
    count[x][y] = c
    kabe = False
    for dx,dy in dxdy:
        nx, ny = x+dx, y+dy
        if not (0<=nx<h and 0<=ny<w):
            continue
        if s[nx][ny]:
            que.appendleft((nx,ny,c))
        else:
            kabe = True
    if not kabe:
        continue
    nc = c+1
    for kx in range(-2,3):
        for ky in range(-2,3):
            nx = x+kx
            ny = y+ky
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > nc:
                que.append((nx,ny,nc))

ans = count[dh][dw]
if ans == inf:
    ans = -1
print(ans)



Fixed submission:
h,w = map(int, input().split())
ch,cw = map(int, input().split())
ch,cw = ch-1, cw-1
dh,dw = map(int, input().split())
dh,dw = dh-1,dw-1
s = [list(map(lambda x: x==".", input())) for i in range(h)]

inf = 2**32-1
count = [[inf]*w for i in range(h)]

from collections import deque
que = deque()
que.append((ch,cw,0))

dxdy = [(-1,0),(0,1),(1,0),(0,-1)]
dxdy1 = [(-1,-1),(-1,-2),(-2,-1),(-2,-2)]
dxdy2 = [(-1,1),(-1,2),(-2,1),(-2,2)]
dxdy3 = [(1,1),(1,2),(2,1),(2,2)]
dxdy4 = [(1,-1),(1,-2),(2,-1),(2,-2)]
while que:
    x,y,c = que.popleft()
    if count[x][y] <= c:
        continue
    count[x][y] = c
    state = [False]*4
    for i, (dx,dy) in enumerate(dxdy):
        nx, ny = x+dx, y+dy
        if not (0<=nx<h and 0<=ny<w):
            continue
        if s[nx][ny]:
            que.appendleft((nx,ny,c))
        else:
            state[i] = True
            nx,ny = nx+dx, ny+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))

    if state[-1] and state[0]:
        for dx,dy in dxdy1:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))

    if state[0] and state[1]:
        for dx,dy in dxdy2:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))
    if state[1] and state[2]:
        for dx,dy in dxdy3:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))
    if state[2] and state[3]:
        for dx,dy in dxdy4:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))

ans = count[dh][dw]
if ans == inf:
    ans = -1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
reader = (s.rstrip() for s in sys.stdin)
input = reader.__next__

h,w = map(int, input().split())
ch,cw = map(int, input().split())
ch,cw = ch-1, cw-1
dh,dw = map(int, input().split())
dh,dw = dh-1,dw-1
s = [list(map(lambda x: x==".", input())) for i in range(h)]

inf = 2**32-1
count = [[inf]*w for i in range(h)]

que = []
que.append((ch,cw,0))

dxdy = [(0,1),(1,0),(0,-1),(-1,0)]

for x,y,c in que:
    if count[x][y] <= c:
        continue
    count[x][y] = c
    kabe = False
    for dx,dy in dxdy:
        nx, ny = x+dx, y+dy
        if not (0<=nx<h and 0<=ny<w):
            continue
        if s[nx][ny]:
            que.append((nx,ny,c))
        else:
            kabe = True
    if not kabe:
        continue
    nc = c+1
    for kx in range(-2,3):
        for ky in range(-2,3):
            nx = x+kx
            ny = y+ky
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > nc:
                que.append((nx,ny,nc))

ans = count[dh][dw]
if ans == inf:
    ans = -1
print(ans)



Fixed submission:
h,w = map(int, input().split())
ch,cw = map(int, input().split())
ch,cw = ch-1, cw-1
dh,dw = map(int, input().split())
dh,dw = dh-1,dw-1
s = [list(map(lambda x: x==".", input())) for i in range(h)]

inf = 2**32-1
count = [[inf]*w for i in range(h)]

from collections import deque
que = deque()
que.append((ch,cw,0))

dxdy = [(-1,0),(0,1),(1,0),(0,-1)]
dxdy1 = [(-1,-1),(-1,-2),(-2,-1),(-2,-2)]
dxdy2 = [(-1,1),(-1,2),(-2,1),(-2,2)]
dxdy3 = [(1,1),(1,2),(2,1),(2,2)]
dxdy4 = [(1,-1),(1,-2),(2,-1),(2,-2)]
while que:
    x,y,c = que.popleft()
    if count[x][y] <= c:
        continue
    count[x][y] = c
    state = [False]*4
    for i, (dx,dy) in enumerate(dxdy):
        nx, ny = x+dx, y+dy
        if not (0<=nx<h and 0<=ny<w):
            continue
        if s[nx][ny]:
            que.appendleft((nx,ny,c))
        else:
            state[i] = True
            nx,ny = nx+dx, ny+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))

    if state[-1] and state[0]:
        for dx,dy in dxdy1:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))

    if state[0] and state[1]:
        for dx,dy in dxdy2:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))
    if state[1] and state[2]:
        for dx,dy in dxdy3:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))
    if state[2] and state[3]:
        for dx,dy in dxdy4:
            nx, ny = x+dx, y+dy
            if 0<=nx<h and 0<=ny<w and s[nx][ny] and count[nx][ny] > c+1:
                que.append((nx,ny,c+1))

ans = count[dh][dw]
if ans == inf:
    ans = -1
print(ans)