Buggy python submission (verdict: Runtime Error):
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(W)]
hori = [[0]*W for i in range(H)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Fixed submission:
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(H)]
hori = [[0]*W for i in range(H)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Buggy python submission (verdict: Runtime Error):
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(W)]
hori = [[0]*W for i in range(W)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Fixed submission:
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(H)]
hori = [[0]*W for i in range(H)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Buggy python submission (verdict: Runtime Error):
import sys

#readline = sys.stdin.readline
_input = open('input')
readline = _input.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(W)]
hori = [[0]*W for i in range(W)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Fixed submission:
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(H)]
hori = [[0]*W for i in range(H)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Buggy python submission (verdict: Runtime Error):
import sys

#readline = sys.stdin.readline
_input = open('input')
readline = _input.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(W)]
hori = [[0]*W for i in range(W)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Fixed submission:
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(H)]
hori = [[0]*W for i in range(H)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Buggy python submission (verdict: Runtime Error):
import sys

#readline = sys.stdin.readline
_input = open('input')
readline = _input.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(W)]
hori = [[0]*W for i in range(W)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)
        sys.stdout.write('{},{}\t'.format(hori[y][x], vert[y][x]))
    print('')

print(ans)

Fixed submission:
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(H)]
hori = [[0]*W for i in range(H)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Buggy python submission (verdict: Runtime Error):
import sys

#readline = sys.stdin.readline
_input = open('input')
readline = _input.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(W)]
hori = [[0]*W for i in range(W)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[x][y] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)

Fixed submission:
import sys

readline = sys.stdin.readline

H, W = map(int, readline().split())
S = [readline().rstrip() for i in range(H)]

vert = [[0]*W for i in range(H)]
hori = [[0]*W for i in range(H)]

for y in range(H):
    for x in range(W):

        if x > 0 and S[y][x - 1] != '#':
            hori[y][x] = hori[y][x - 1]
        elif S[y][x] == '#':
            hori[y][x] = 0
        else:
            # hori
            count = 1
            while x + count < W and S[y][x + count] == '.':
                count += 1
            hori[y][x] = count

        if y > 0 and S[y - 1][x] != '#':
            vert[y][x] = vert[y - 1][x]
        elif S[y][x] == '#':
            vert[y][x] = 0
        else:
            # hori
            count = 1
            while y + count < H and S[y + count][x] == '.':
                count += 1
            vert[y][x] = count

ans = 0
for y in range(H):
    for x in range(W):
        a = hori[y][x] + vert[y][x] - 1
        ans = max(a, ans)

print(ans)