Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(lambda x:int(x)-1,input().split())
dh,dw=map(lambda x:int(x)-1,input().split())
tizu=[]
d=deque()
d.appendleft([ch,cw])
cost=[[-1 for i in range(w)]for j in range(h)]
dx=[1,0,-1,0,-2,-2,-2,-2,-2,-1,-1,-1,-1,0,0,1,1,1,1,2,2,2,2,2]
dy=[0,1,0,-1,-2,-1,0,1,2,-2,-1,1,2,-2,2,-2,-1,1,2,-2,-1,0,1,2]
for i in range(h):
    tizu.append(input())
cost[ch][cw]=0
while(d):
    x,y=d.popleft()
    for i in range(4):
        nx=x+dx[i]
        ny=y+dy[i]
        ####行ったことある、かつ、コストが手前より高い
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1 and cost[nx][ny]<=cost[x][y]):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]
            d.appendleft([nx,ny])
    
    for i in range(4,24):
        nx=x+dx[i]
        ny=y+dy[i]
        if(nx<0 or ny<0 or nx>=h or ny>=w):
            continue
        if(cost[nx][ny]>-1):
            continue
        if(tizu[nx][ny]=='.'):
            cost[nx][ny]=cost[x][y]+1
            d.append([nx,ny])

print(cost[dh][dw])