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)

import sys
sys.setrecursionlimit(10**7)

h, w = map(int, input().split())
s = [list(input()) for _ in range(h)]
visited = [[False] * w for _ in range(h)]

def dfs(y, x):
    visited[y][x] = True
    blk, wht = 0, 0

    for dy, dx in ((-1, 0), (0, -1), (1, 0), (0, 1)):
        ny, nx = y+dy, x+dx
        if (not (0 <= ny < h)) or (not (0 <= nx < w)) or visited[ny][nx]: continue
        if s[y][x] != s[ny][nx]:
            nb, nw = dfs(ny, nx)
            blk += nb; wht += nw
    
    if s[y][x] == "#": blk += 1
    else: wht += 1

    return blk, wht

ans = 0
for i in range(h):
    for j in range(w):
        if not visited[i][j]:
            blk, wht = dfs(i, j)
            ans += blk * wht

print(ans)