Buggy python submission (verdict: Runtime Error):
import numpy as np

def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

def main():
    H, W = map(int, input().split())
    # 黒0，白1，padding2
    S = [[2] * (W+2)]
    for _ in range(H):
        S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
    S.append([2] * (W+2))
    S = np.array(S, dtype=np.int8)
    num_comb = 0
    for i in range(1, H+1):
        for j in range(1, W+1):
            if S[i][j] == 0:
                num_color = [0, 0]
                num_comb += trace(i, j, S, 0, num_color)
    print(num_comb)

main()

Fixed submission:
import sys
sys.setrecursionlimit(100000000)

def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

def main():
    H, W = map(int, input().split())
    # 黒0，白1，padding2
    S = [[2] * (W+2)]
    for _ in range(H):
        S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
    S.append([2] * (W+2))
    num_comb = 0
    for i in range(1, H+1):
        for j in range(1, W+1):
            if S[i][j] == 0:
                num_color = [0, 0]
                num_comb += trace(i, j, S, 0, num_color)
    print(num_comb)

main()

Buggy python submission (verdict: Runtime Error):
def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

def main():
    H, W = map(int, input().split())
    # 黒0，白1，padding2
    S = [[2] * (W+2)]
    for _ in range(H):
        S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
    S.append([2] * (W+2))
    num_comb = 0
    for i in range(1, H+1):
        for j in range(1, W+1):
            if S[i][j] == 0:
                num_color = [0, 0]
                num_comb += trace(i, j, S, 0, num_color)
    print(num_comb)

main()

Fixed submission:
import sys
sys.setrecursionlimit(100000000)

def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

def main():
    H, W = map(int, input().split())
    # 黒0，白1，padding2
    S = [[2] * (W+2)]
    for _ in range(H):
        S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
    S.append([2] * (W+2))
    num_comb = 0
    for i in range(1, H+1):
        for j in range(1, W+1):
            if S[i][j] == 0:
                num_color = [0, 0]
                num_comb += trace(i, j, S, 0, num_color)
    print(num_comb)

main()

Buggy python submission (verdict: Runtime Error):
def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

H, W = map(int, input().split())
# 黒0，白1，padding2
S = [[2] * (W+2)]
for _ in range(H):
    S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
S.append([2] * (W+2))
# print(S)
num_comb = 0
for i in range(1, H+1):
    for j in range(1, W+1):
        if S[i][j] == 0:
            num_color = [0, 0]
            num_comb += trace(i, j, S, 0, num_color)
print(num_comb)


Fixed submission:
import sys
sys.setrecursionlimit(100000000)

def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

def main():
    H, W = map(int, input().split())
    # 黒0，白1，padding2
    S = [[2] * (W+2)]
    for _ in range(H):
        S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
    S.append([2] * (W+2))
    num_comb = 0
    for i in range(1, H+1):
        for j in range(1, W+1):
            if S[i][j] == 0:
                num_color = [0, 0]
                num_comb += trace(i, j, S, 0, num_color)
    print(num_comb)

main()

Buggy python submission (verdict: Runtime Error):
def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

H, W = map(int, input().split())
# 黒0，白1，padding2
S = [[2] * (W+2)]
for _ in range(H):
    S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
S.append([2] * (W+2))
# print(S)
num_comb = 0
for i in range(1, H+1):
    for j in range(1, W+1):
        if S[i][j] == 0:
            num_color = [0, 0]
            num_comb += trace(i, j, S, 0, num_color)
print(num_comb)

Fixed submission:
import sys
sys.setrecursionlimit(100000000)

def trace(i, j, S, col, num_color):
    next_col = 1 - col
    num_color[col] += 1
    S[i][j] = 2
    if S[i-1][j] == next_col:
        trace(i-1, j, S, next_col, num_color)
    if S[i][j-1] == next_col:
        trace(i, j-1, S, next_col, num_color)
    if S[i+1][j] == next_col:
        trace(i+1, j, S, next_col, num_color)
    if S[i][j+1] == next_col:
        trace(i, j+1, S, next_col, num_color)
    return num_color[0] * num_color[1]

def main():
    H, W = map(int, input().split())
    # 黒0，白1，padding2
    S = [[2] * (W+2)]
    for _ in range(H):
        S.append([2] + [0 if s == '#' else 1 for s in input()] + [2])
    S.append([2] * (W+2))
    num_comb = 0
    for i in range(1, H+1):
        for j in range(1, W+1):
            if S[i][j] == 0:
                num_color = [0, 0]
                num_comb += trace(i, j, S, 0, num_color)
    print(num_comb)

main()