Problem:
Score : 300 points

Problem Statement

There is a grid with H rows and W columns, where each square is painted black or white.

You are given H strings S_1, S_2, ..., S_H, each of length W.
If the square at the i-th row from the top and the j-th column from the left is painted black, the j-th character in the string S_i is #; if that square is painted white, the j-th character in the string S_i is ..

Find the number of pairs of a black square c_1 and a white square c_2 that satisfy the following condition:

There is a path from the square c_1 to the square c_2 where we repeatedly move to a vertically or horizontally adjacent square through an alternating sequence of black and white squares: black, white, black, white...

Constraints

1 \leq H, W \leq 400

|S_i| = W (1 \leq i \leq H)

For each i (1 \leq i \leq H), the string S_i consists of characters # and ..

Input

Input is given from Standard Input in the following format:

H W
S_1
S_2
:
S_H

Output

Print the answer.

Sample Input 1

3 3
.#.
..#
#..

Sample Output 1

10

Some of the pairs satisfying the condition are ((1, 2), (3, 3)) and ((3, 1), (3, 2)), where (i, j) denotes the square at the i-th row from the top and the j-th column from the left.

Sample Input 2

2 4
....
....

Sample Output 2

0

Sample Input 3

4 3
###
###
...
###

Sample Output 3

6

Solution in Python (3.4.3) (judge verdict: Accepted)

# -*- coding: utf-8 -*-
"""
Created on Sat Jan 12 18:50:46 2019
AIsingD
@author: maezawa
"""

h, w = list(map(int, input().split()))
a = [list('*'*(w+2))]
for _ in range(h):
    a.append(['*']+list(input())+['*'])
a.append(list('*'*(w+2)))
b = [[0]*(w+2) for _ in range(h+2)]
#print(a)

dirs = [(-1,0),(0,1),(1,0),(0,-1)]
ans = 0

for i in range(1, h+1):
    for j in range(1, w+1):
        if a[i][j] == '#' and b[i][j] == 0:
            stackb = [(i, j)]
            cntb = 0
            cntw = 0
            stackw = []
            while stackb:
                inext, jnext = stackb.pop(-1)
                if b[inext][jnext] != 0:
                    continue
                cntb += 1
                b[inext][jnext] = 1
                for direction in dirs:
                    inextb = inext + direction[0]
                    jnextb = jnext + direction[1]
                    if a[inextb][jnextb] == '.' and b[inextb][jnextb] == 0:
                        stackw.append((inextb,jnextb))
                while stackw:
                    inext, jnext = stackw.pop(-1)
                    if b[inext][jnext] != 0:
                        continue
                    cntw += 1
                    b[inext][jnext] = 1
                    for direction in dirs:
                        inextw = inext + direction[0]
                        jnextw = jnext + direction[1]
                        if a[inextw][jnextw] == '#' and b[inextw][jnextw] == 0:
                            stackb.append((inextw,jnextw))

            #print((i,j),cntb, cntw)
            ans += cntb*cntw
print(ans)