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 Ruby (2.3.3) (judge verdict: Accepted)

h,w = gets.split.map(&:to_i)
used = Array.new(h).map{Array.new(w,false)}
s = h.times.map{gets.chomp}
ans = 0
h.times do |i|
    w.times do |j|
        next if used[i][j]
        q = [[i,j]]
        used[i][j] = true
        a = b = 0
        if s[i][j] == "."
            a += 1
        else
            b += 1
        end
        while q.any?
            x,y = q.shift
            if x != 0 && s[x][y] != s[x-1][y] && !used[x-1][y]
                q.push([x-1,y])
                used[x-1][y] = true
                if s[x-1][y] == "."
                    a += 1
                else
                    b += 1
                end
            end
            if x != h-1 && s[x][y] != s[x+1][y] && !used[x+1][y]
                q.push([x+1,y])
                used[x+1][y] = true
                if s[x+1][y] == "."
                    a += 1
                else
                    b += 1
                end
            end
            if y != 0 && s[x][y] != s[x][y-1] && !used[x][y-1]
                q.push([x,y-1])
                used[x][y-1] = true
                if s[x][y-1] == "."
                    a += 1
                else
                    b += 1
                end
            end
            if y != w-1 && s[x][y] != s[x][y+1] && !used[x][y+1]
                q.push([x,y+1])
                used[x][y+1] = true
                if s[x][y+1] == "."
                    a += 1
                else
                    b += 1
                end
            end
        end
        ans += a*b
    end
end
puts ans