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 Rust (1.15.1) (judge verdict: Wrong Answer)

use std::collections::BinaryHeap;
use std::collections::HashMap;
use std::collections::HashSet;
use std::collections::VecDeque;

macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        let mut next = || { iter.next().unwrap() };
        input_inner!{next, $($r)*}
    };
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes
                .by_ref()
                .map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr, ) => {};

    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
    ($next:expr, mut $var:ident : $t:tt $($r:tt)*) => {
        let mut $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => {
        ( $(read_value!($next, $t)),* )
    };

    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };

    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };

    ($next:expr, usize1) => {
        read_value!($next, usize) - 1
    };

    ($next:expr, $t:ty) => {
        $next().parse::<$t>().expect("Parse error")
    };
}

const MOD: i64 = 1_000_000_007;

struct Mass {
    x: usize,
    y: usize,
    c: char,
}

fn main() {
    input! {
        h: usize,
        w: usize,
        s: [chars; h]
    }

    let mut f = vec![vec![false; w]; h];
    let mut num = 0;
    for i in 0..h {
        for j in 0..w {
            if f[i][j] == false {
                let mut c1 = 1;
                let mut c2 = 0;
                let mut q = VecDeque::new();
                q.push_back(Mass {
                    x: j,
                    y: i,
                    c: s[i][j],
                });
                f[i][j] = true;

                while let Some(cur) = q.pop_front() {
                    for (dx, dy) in [0, 0, -1, 1].iter().zip([-1, 1, 0, 0].iter()) {
                        let nx = (cur.x as i64) + dx;
                        let ny = (cur.y as i64) + dy;
                        if 0 <= nx && nx < w as i64 && 0 <= ny && ny < h as i64 {
                            if f[ny as usize][nx as usize] == false
                                && cur.c != s[ny as usize][nx as usize]
                            {
                                q.push_back(Mass {
                                    x: nx as usize,
                                    y: ny as usize,
                                    c: s[ny as usize][nx as usize],
                                });
                                f[ny as usize][nx as usize] = true;
                                if s[i][j] == s[ny as usize][nx as usize] {
                                    c1 += 1;
                                } else {
                                    c2 += 1;
                                }
                            }
                        }
                    }
                }
                num += c1 * c2;
            }
        }
    }

    println!("{}", num);
}