Buggy python submission (verdict: Time Limit Exceeded):
from pprint import pprint
from collections import deque
h, w = map(int, input().split())

m = deque([])
mv = deque([])
mh = deque([])

for i in range(h):
    mh.append(deque([0] * w))
for i in range(h):
    mv.append(deque([0] * w))

for i in range(h):
    m.append(input())

for i in range(h):
    c = 0
    for j in range(w):
        if m[i][j] == "#":
            mh[i][j] = 0
            for k in range(c):
                mh[i][j - k - 1] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mh[i][w - 1 - k] = c

for i in range(w):
    c = 0
    for j in range(h):
        if m[j][i] == "#":
            mv[j][i] = 0
            for k in range(c):
                mv[j - k - 1][i] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mv[h - 1 - k][i] = c

res = 0
for i in range (h):
    for j in range(w):
        res = max(res, mv[i][j] + mh[i][j])
print(res - 1)


#pprint(mh)
#pprint(mv)


Fixed submission:
h, w = map(int, input().split())

m = list()
mv = list()
mh = list()

for i in range(h):
    mh.append([0] * w)
for i in range(h):
    mv.append([0] * w)

for i in range(h):
    m.append(input())

for i in range(h):
    c = 0
    for j in range(w):
        if m[i][j] == "#":
            mh[i][j] = 0
            for k in range(c):
                mh[i][j - k - 1] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mh[i][w - 1 - k] = c

for i in range(w):
    c = 0
    for j in range(h):
        if m[j][i] == "#":
            mv[j][i] = 0
            for k in range(c):
                mv[j - k - 1][i] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mv[h - 1 - k][i] = c

res = 0
for i in range (h):
    for j in range(w):
        res = max(res, mv[i][j] + mh[i][j])
print(res - 1)

Buggy python submission (verdict: Time Limit Exceeded):
from pprint import pprint
from collections import deque
h, w = map(int, input().split())

m = deque([])
mv = deque([])
mh = deque([])

for i in range(h):
    mh.append([0] * w)
for i in range(h):
    mv.append([0] * w)

for i in range(h):
    m.append(input())

for i in range(h):
    c = 0
    for j in range(w):
        if m[i][j] == "#":
            mh[i][j] = 0
            for k in range(c):
                mh[i][j - k - 1] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mh[i][w - 1 - k] = c

for i in range(w):
    c = 0
    for j in range(h):
        if m[j][i] == "#":
            mv[j][i] = 0
            for k in range(c):
                mv[j - k - 1][i] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mv[h - 1 - k][i] = c

res = 0
for i in range (h):
    for j in range(w):
        res = max(res, mv[i][j] + mh[i][j])
print(res - 1)

Fixed submission:
h, w = map(int, input().split())

m = list()
mv = list()
mh = list()

for i in range(h):
    mh.append([0] * w)
for i in range(h):
    mv.append([0] * w)

for i in range(h):
    m.append(input())

for i in range(h):
    c = 0
    for j in range(w):
        if m[i][j] == "#":
            mh[i][j] = 0
            for k in range(c):
                mh[i][j - k - 1] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mh[i][w - 1 - k] = c

for i in range(w):
    c = 0
    for j in range(h):
        if m[j][i] == "#":
            mv[j][i] = 0
            for k in range(c):
                mv[j - k - 1][i] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mv[h - 1 - k][i] = c

res = 0
for i in range (h):
    for j in range(w):
        res = max(res, mv[i][j] + mh[i][j])
print(res - 1)

Buggy python submission (verdict: Time Limit Exceeded):
h, w = map(int, input().split())
 
m = list()
mv = list()
mh = list()
 
for i in range(h):
    mh.append([0] * w)
for i in range(h):
    mv.append([0] * w)
 
for i in range(h):
    m.append(input())
 
for i in range(h):
    c = 0
    for j in range(w):
        if m[i][j] == "#":
            mh[i][j] = 0
            for k in range(c):
                mh[i][j - k - 1] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mh[i][w - 1 - k] = c
 
for i in range(w):
    c = 0
    for j in range(h):
        if m[j][i] == "#":
            mv[j][i] = 0
            for k in range(c):
                mv[j - k - 1][i] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mv[h - 1 - k][i] = c
 
res = 0
for i in range (h):
    for j in range(w):
        res = max(res, mv[i][j] + mh[i][j])
print(res - 1)

Fixed submission:
h, w = map(int, input().split())

m = list()
mv = list()
mh = list()

for i in range(h):
    mh.append([0] * w)
for i in range(h):
    mv.append([0] * w)

for i in range(h):
    m.append(input())

for i in range(h):
    c = 0
    for j in range(w):
        if m[i][j] == "#":
            mh[i][j] = 0
            for k in range(c):
                mh[i][j - k - 1] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mh[i][w - 1 - k] = c

for i in range(w):
    c = 0
    for j in range(h):
        if m[j][i] == "#":
            mv[j][i] = 0
            for k in range(c):
                mv[j - k - 1][i] = c
            c = 0
        else:
            c += 1
    for k in range(c):
        mv[h - 1 - k][i] = c

res = 0
for i in range (h):
    for j in range(w):
        res = max(res, mv[i][j] + mh[i][j])
print(res - 1)