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 C++14 (GCC 5.4.1) (judge verdict: Runtime Error)

#include<stdio.h>
#include<iostream>
#include<algorithm>
#include<set>
#include<math.h>
#include<queue>
#include<string.h>
#include<string>
#include<map>
#include<stack>
#include<vector>
#define mod 998244353
using namespace std;
struct str {
	int x, y;
};
struct str2 {
	int cur;
	double cost, time;
	bool operator < (const str2&A)const {
		return cost > A.cost;
	}
};
priority_queue<str2> pq;
vector<str> vec[5611];
vector<int> back[600];
int n, t, w, k, h, m, e, q;
str arr[6600];
int bd[600];
int ans;
int X[4] = { 0,0,1,-1 };
int Y[4] = { 1,-1,0,0 };
string s[100000];
bool chk[600][600];
void dfs(int x, int y) {
	chk[x][y] = true;
	if (s[x][y] == '#') {
		for (int i = 0; i < 4; i++) {
			int nx = x + X[i], ny = y + Y[i];
			if (0 <= nx && nx < h && 0 <= ny && ny < w) {
				if (chk[nx][ny]) continue;
				if (0 <= nx && nx < h && 0 <= ny && ny < w)
					if (s[x + X[i]][y + Y[i]] == '.')
						dfs(x + X[i], y + Y[i]);
			}
		}
	}
	if (s[x][y] == '.') {
		ans++;
		for (int i = 0; i < 4; i++) {
			int nx = x + X[i], ny = y + Y[i];
			if (0 <= nx && nx < h && 0 <= ny && ny < w) {
				if (chk[nx][ny]) continue;
				if (s[x + X[i]][y + Y[i]] == '#')
					dfs(x + X[i], y + Y[i]);
			}
		}
	}
	return;
}
int main() {
	cin >> h >> w;
	for (int i = 0; i < h; i++) {
		cin >> s[i];
	}
	int cnt = 0;
	for (int i = 0; i < h; i++)
		for (int j = 0; j < w; j++)
			if (s[i][j] == '#') {
				arr[cnt++] = { i,j };
			}
	for (int i = 0; i < cnt; i++) {
		memset(chk, 0, sizeof(chk));
		dfs(arr[i].x, arr[i].y);
	}
	cout << ans << endl;
	return 0;
}