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 Kotlin (1.0.0) (judge verdict: Accepted)

var black = 0L
var white = 0L
val map = mutableListOf<MutableList<Char>>()

fun main(args: Array<String>) {
    val (h, w) = readLine()!!.split(' ').map(String::toInt)
    map.add(Array(w + 2) { 'X' }.toMutableList())
    (1..h).forEach {
        val element = readLine()!!.toCharArray().toMutableList()
        element.add(0, 'X')
        element.add(element.size, 'X')
        map.add(element)
    }
    map.add(Array(w + 2) { 'X' }.toMutableList())

    var ans = 0L
    for (r in 1..h) {
        for (c in 1..w) {
            black = 0L
            white = 0L
            check(r, c)
            ans += black * white
        }
    }
    println(ans)
}

fun check(r: Int, c: Int) {
    val current = map[r][c]
    when (current) {
        'X' -> return
        '#' -> {
            black++
            map[r][c] = 'X'
        }
        '.' -> {
            white++
            map[r][c] = 'X'
        }
    }
    if (map[r - 1][c] != current) check(r - 1, c)
    if (map[r][c - 1] != current) check(r, c - 1)
    if (map[r + 1][c] != current) check(r + 1, c)
    if (map[r][c + 1] != current) check(r, c + 1)
}