Buggy python submission (verdict: Time Limit Exceeded):
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    cnt = 0
    for w in range(W):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        left[h][w] = cnt

for h in range(H):
    cnt = 0
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        right[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        up[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        down[h][w] = cnt

ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)


Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Runtime Error):
import numpy as np 
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

yoko = [[0 for _ in range(W)] for _ in range(H)]
tate =  [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    cnt = 0
    for w in range(W):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        yoko[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        tate[h][w] = cnt

tate = np.array(tate)
yoko = np.array(yoko)

for h in range(H):
    my_max = 0
    for w in range(W):
        if yoko[h][W - 1 - w] != 0:
            my_max = max(my_max, yoko[h][W - 1 - w])
            yoko[h][W - 1 - w] = my_max
        else:
            my_max = 0

tate = tate.T

for h in range(W):
    my_max = 0
    for w in range(H):
        if tate[h][H - 1 - w] != 0:
            my_max = max(my_max, tate[h][H - 1 - w])
            tate[h][H - 1 - w] = my_max
        else:
            my_max = 0
            
tate = tate.T
ans = tate + yoko - 1

print(np.max(ans.ravel()))


Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1
        else:
            left[h][w] = 0

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
        else:
            right[h][w] = 0
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
        else:
            up[h][w] = 0

for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
        else:
            down[h][w] = 0

ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    cnt = 0
    for w in range(W):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        left[h][w] = cnt

for h in range(H):
    cnt = 0
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        right[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        up[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        down[h][w] = cnt

ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np 
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

yoko = [[0 for _ in range(W)] for _ in range(H)]
tate =  [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    cnt = 0
    for w in range(W):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        yoko[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        tate[h][w] = cnt

tate = np.array(tate)
yoko = np.array(yoko)

for h in range(H):
    my_max = 0
    for w in range(W):
        if yoko[h][W - 1 - w] != 0:
            my_max = max(my_max, yoko[h][W - 1 - w])
            yoko[h][W - 1 - w] = my_max
        else:
            my_max = 0

tate = tate.T

for h in range(W):
    my_max = 0
    for w in range(H):
        if tate[h][H - 1 - w] != 0:
            my_max = max(my_max, tate[h][H - 1 - w])
            tate[h][H - 1 - w] = my_max
        else:
            my_max = 0
            
tate = tate.T

ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, tate[h][w] + yoko[h][w] - 1)
print(ans)



Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Runtime Error):
import numpy as np 
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

yoko = [[0 for _ in range(W)] for _ in range(H)]
tate =  [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    cnt = 0
    for w in range(W):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        yoko[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        tate[h][w] = cnt

tate = np.array(tate)
yoko = np.array(yoko)

for h in range(H):
    my_max = 0
    for w in range(W):
        if yoko[h][W - 1 - w] != 0:
            my_max = max(my_max, yoko[h][W - 1 - w])
            yoko[h][W - 1 - w] = my_max
        else:
            my_max = 0

tate = tate.T

for h in range(W):
    my_max = 0
    for w in range(H):
        if tate[h][H - 1 - w] != 0:
            my_max = max(my_max, tate[h][H - 1 - w])
            tate[h][H - 1 - w] = my_max
        else:
            my_max = 0
            
tate = tate.T

ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, tate[w][h] + yoko[w][h] - 1)
print(ans)

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np 
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

yoko = [[0 for _ in range(W)] for _ in range(H)]
tate =  [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    cnt = 0
    for w in range(W):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        yoko[h][w] = cnt

for w in range(W):
    cnt = 0
    for h in range(H):
        if grid[h][w] == ".":
            cnt += 1
        else:
            cnt = 0
        tate[h][w] = cnt

tate = np.array(tate)
yoko = np.array(yoko)

for h in range(H):
    my_max = 0
    for w in range(W):
        if yoko[h][W - 1 - w] != 0:
            my_max = max(my_max, yoko[h][W - 1 - w])
            yoko[h][W - 1 - w] = my_max
        else:
            my_max = 0

tate = tate.T

for h in range(W):
    my_max = 0
    for w in range(H):
        if tate[h][H - 1 - w] != 0:
            my_max = max(my_max, tate[h][H - 1 - w])
            tate[h][H - 1 - w] = my_max
        else:
            my_max = 0
            
tate = tate.T
ans = tate + yoko - 1

print(np.max(ans.ravel()))

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

def dfs(h, w):
    cnt = 0
    if grid[h][w] == "#":
        return cnt
    q = deque([(h, w)])
    cnt += 1
    h, w = q.pop()
    for i, j in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
        if 0 <= h + i < H and 0 <= w + j < W and grid[h + i][w + j] == ".":
                cnt += 1
                q.append((h + i, w + j, (i, j)))
    while q:
        h, w, direct = q.pop()
        i, j = direct
        if 0 <= h + i < H and 0 <= w + j < W and grid[h + i][w + j] == ".":
            cnt += 1
            q.append((h + i, w + j, (i, j)))
 
    return cnt 
    
ans = 0
for h in range(H):
    for w in range(W):
        ans = max(ans, dfs(h, w))
print(ans)

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

def dfs(h, w):
    cnt = 0
    if grid[h][w] == "#":
        return cnt
    q = deque([(h, w, "No")])
    cnt += 1
    while q:
        h, w, direct = q.pop()
        for i, j in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
            if direct == "No" or direct == (i, j):
                if 0 <= h + i < H and 0 <= w + j < W and grid[h + i][w + j] == ".":
                        cnt += 1
                        q.append((h + i, w + j, (i, j)))
 
    return cnt 
    
ans = 0
for h in range(H):
    for w in range(W):
        ans = max(ans, dfs(h, w))
print(ans)

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

def dfs(h, w):
    cnt = 0
    if grid[h][w] == "#":
        return cnt
    q = deque([(h, w, "No")])
    cnt += 1
    while q:
        h, w, direct = q.pop()
        for i, j in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
            if 0 <= h + i < H and 0 <= w + j < W and grid[h + i][w + j] == ".":
                if direct == "No" or direct == (i, j):
                    cnt += 1
                    q.append((h + i, w + j, (i, j)))
            else:
                continue
    return cnt 
    
ans = 0
for h in range(H):
    for w in range(W):
        ans = max(ans, dfs(h, w))
print(ans)

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])

def dfs(h, w):
    done = [[0 for _ in range(W)] for _ in range (H)]
    cnt = 0
    if grid[h][w] == "#":
        return cnt
    q = deque([(h, w, "No")])
    cnt += 1
    while q:
        h, w, direct = q.pop()
        for i, j in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
            if 0 <= h + i < H and 0 <= w + j < W and grid[h + i][w + j] == "." and done[h + i][w + j] == 0:
                if direct == "No" or direct == (i, j):
                    cnt += 1
                    q.append((h + i, w + j, (i, j)))
                    done[h + i][w + j] = 1
    return cnt 
    
ans = 0
for h in range(H):
    for w in range(W):
        ans = max(ans, dfs(h, w))
print(ans)

Fixed submission:
H, W = map(int, input().split())
grid = []
for _ in range(H):
    grid.append([s for s in input()])
    
left = [[0 for _ in range(W)] for _ in range(H)]
right = [[0 for _ in range(W)] for _ in range(H)]
up = [[0 for _ in range(W)] for _ in range(H)]
down = [[0 for _ in range(W)] for _ in range(H)]

for h in range(H):
    for w in range(W):
        if grid[h][w] == ".":
            if w == 0:
                left[h][w] = 1
            else:
                left[h][w] += left[h][w - 1] + 1

for h in range(H):
    for w in range(W)[::-1]:
        if grid[h][w] == ".":
            if w == W - 1:
                right[h][w] = 1
            else:
                right[h][w] += right[h][w + 1] + 1
            
for w in range(W):
    for h in range(H):
        if grid[h][w] == ".":
            if h == 0:
                up[h][w] = 1
            else:
                up[h][w] += up[h - 1][w] + 1
                
for w in range(W):
    for h in range(H)[::-1]:
        if grid[h][w] == ".":
            if h == H - 1:
                down[h][w] = 1
            else:
                down[h][w] += down[h + 1][w] + 1
                
ans = -10000
for h in range(H):
    for w in range(W):
        ans = max(ans, up[h][w] + down[h][w] + right[h][w] + left[h][w] - 3)
print(ans)