Buggy python submission (verdict: Time Limit Exceeded):
import sys

sys.setrecursionlimit(10**7)

h,w = map(int,input().split())
si = [input() for i in range(h)]

check = [-1]*(h*w)

#print(check,check==-1)
#exit()

vx = [0,1,0,-1]
vy = [1,0,-1,0]

def dfs(num,clr):
    #print(min(check))
    #if min(check) > -1:
    #    return
    
    y = num//w
    x = num%w
    for j in range(4):
        ny = y + vy[j]
        nx = x + vx[j]
        if ny >= 0 and ny < h and nx >= 0 and nx < w:
            new_num = ny*w+nx
            if check[new_num] != -1:
                continue
            #print(new_num,num,clr,si[ny][nx])
            if clr == '#':
                #print(ny,nx)
                if si[ny][nx] == '.':
                    check[new_num] = check[num]
                    dfs(new_num,'.')
            else:
                    
                if si[ny][nx] == '#':
                    check[new_num] = check[num]
                    dfs(new_num,'#')
            #print(check)

for i in range(h*w):
    #print(i)
    y = i//w
    x = i%w
    if si[y][x] == '#':
        if check[i] != -1:
            continue
        check[i] = i
        dfs(i,'#')
        #print(check)
        #exit()

ans = 0

li = [0]*(h*w+1)

for i in range(h):
    for j in range(w):
        if si[i][j] == '.':
            li[check[i*w+j]] += 1

#print(li)

for i in range(h):
    for j in range(w):
        if si[i][j] == '#':
            ans += li[check[i*w+j]]
            
print(ans)

Fixed submission:
h,w = map(int,input().split())
si = [input() for i in range(h)]

class UnionFind:
    def __init__(self, n):
        self.par = [i for i in range(n+1)]
        self.rank = [0] * (n+1)
        self.size = [1 for _ in range(n+1)]
 
    # 検索
    def find(self, x):
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]
 
    # 併合
    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if self.rank[x] < self.rank[y]:
            self.par[x] = y
            self.size[y] += self.size[x]
        else:
            self.par[y] = x
            self.size[x] += self.size[y]
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
 
    # 同じ集合に属するか判定
    def same_check(self, x, y):
        return self.find(x) == self.find(y)
    
ki = UnionFind(h*w)

vx = [0,1,0,-1]
vy = [1,0,-1,0]

for i in range(h):
    for j in range(w):
        if si[i][j] == '#':
            #print(i,j,i,j)
            for k in range(4):
                ny = i + vy[k]
                nx = j + vx[k]
                if ny >= 0 and ny < h and nx >= 0 and nx < w:
                    #print(ny,nx)
                    if si[ny][nx] == '.':
                        #print(i,j,ny,nx)
                        #print(ki.same_check(i*w+j,ny*w+nx))
                        if ki.same_check(i*w+j,ny*w+nx) == True:
                            continue
                        #print(i,j,k)
                        ki.union(i*w+j,ny*w+nx)
                        #print(ki.par)
ans = 0
#exit()


#print(ki.size)
#print(ki.par)
li = [0]*(h*w+1)

for i in range(h):
    for j in range(w):
        #print(ki.find(i*w+j),1111111)
        ki.find(i*w+j)
        """
        if si[i][j] == '.':
            li[ki.find(i*w+h)] += 1
            print(ki.find(i*w+h))
        """
#print(ki.par)
for i in range(h):
    for j in range(w):
        if si[i][j] == '.':
            li[ki.par[i*w+j]] += 1
            #print(ki.par[i*w+h],ki.par)
#print(li)
#print(ki.par)

for i in range(h):
    for j in range(w):
        if si[i][j] == '#':
            #print(ki.size[i*w+j])
            #print(i,j)
            #tmp = 
            #print(ki.find(i*w+j))
            ans += li[ki.find(i*w+j)]
            #print(ans,i,j)
            
print(ans)

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

h,w = map(int,input().split())
si = [input() for i in range(h)]

q = queue.Queue()

check = [-1]*(h*w)

#print(check,check==-1)
#exit()

vx = [0,1,0,-1]
vy = [1,0,-1,0]

def dfs(num,clr):
    #print(min(check))
    #if min(check) > -1:
    #    return
    
    y = num//w
    x = num%w
    for j in range(4):
        ny = y + vy[j]
        nx = x + vx[j]
        if ny >= 0 and ny < h and nx >= 0 and nx < w:
            new_num = ny*w+nx
            if check[new_num] != -1:
                continue
            #print(new_num,num,clr,si[ny][nx])
            if clr == '#':
                #print(ny,nx)
                if si[ny][nx] == '.':
                    check[new_num] = check[num]
                    dfs(new_num,'.')
            else:
                    
                if si[ny][nx] == '#':
                    check[new_num] = check[num]
                    dfs(new_num,'#')
            #print(check)

for i in range(h*w):
    #print(i)
    y = i//w
    x = i%w
    if si[y][x] == '#':
        if check[i] != -1:
            continue
        check[i] = i
        dfs(i,'#')
        #print(check)
        #exit()

ans = 0

li = [0]*(h*w+1)

for i in range(h):
    for j in range(w):
        if si[i][j] == '.':
            li[check[i*w+j]] += 1

#print(li)

for i in range(h):
    for j in range(w):
        if si[i][j] == '#':
            ans += li[check[i*w+j]]
            
print(ans)

Fixed submission:
h,w = map(int,input().split())
si = [input() for i in range(h)]

class UnionFind:
    def __init__(self, n):
        self.par = [i for i in range(n+1)]
        self.rank = [0] * (n+1)
        self.size = [1 for _ in range(n+1)]
 
    # 検索
    def find(self, x):
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]
 
    # 併合
    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if self.rank[x] < self.rank[y]:
            self.par[x] = y
            self.size[y] += self.size[x]
        else:
            self.par[y] = x
            self.size[x] += self.size[y]
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
 
    # 同じ集合に属するか判定
    def same_check(self, x, y):
        return self.find(x) == self.find(y)
    
ki = UnionFind(h*w)

vx = [0,1,0,-1]
vy = [1,0,-1,0]

for i in range(h):
    for j in range(w):
        if si[i][j] == '#':
            #print(i,j,i,j)
            for k in range(4):
                ny = i + vy[k]
                nx = j + vx[k]
                if ny >= 0 and ny < h and nx >= 0 and nx < w:
                    #print(ny,nx)
                    if si[ny][nx] == '.':
                        #print(i,j,ny,nx)
                        #print(ki.same_check(i*w+j,ny*w+nx))
                        if ki.same_check(i*w+j,ny*w+nx) == True:
                            continue
                        #print(i,j,k)
                        ki.union(i*w+j,ny*w+nx)
                        #print(ki.par)
ans = 0
#exit()


#print(ki.size)
#print(ki.par)
li = [0]*(h*w+1)

for i in range(h):
    for j in range(w):
        #print(ki.find(i*w+j),1111111)
        ki.find(i*w+j)
        """
        if si[i][j] == '.':
            li[ki.find(i*w+h)] += 1
            print(ki.find(i*w+h))
        """
#print(ki.par)
for i in range(h):
    for j in range(w):
        if si[i][j] == '.':
            li[ki.par[i*w+j]] += 1
            #print(ki.par[i*w+h],ki.par)
#print(li)
#print(ki.par)

for i in range(h):
    for j in range(w):
        if si[i][j] == '#':
            #print(ki.size[i*w+j])
            #print(i,j)
            #tmp = 
            #print(ki.find(i*w+j))
            ans += li[ki.find(i*w+j)]
            #print(ans,i,j)
            
print(ans)