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 (2.7.1) (judge verdict: Accepted)

#input of int(split by space)
def get_i()
  return gets.chomp.split(" ").map(&:to_i)
end
#input of float(split by space)
def get_f()
  return gets.chomp.split(" ").map(&:to_f)
end
#input of string(split by space)
def get()
  return gets.chomp.split(" ")
end
#input of string(split per one character)
def get_nsp()
  return gets.chomp.split("")
end
#yes or no decision
def yn_judge(bool,y="Yes",n="No")
  return bool ? y : n 
end
#create of array
def array(size1,init=nil,size2=-1)
  if size2==-1
      return Array.new(size1){init}
  else
      return Array.new(size2){Array.new(size1){init}}
  end
end

def max(a,b)
    return a>b ? a : b
end

def min(a,b)
    return a>b ? b : a
end

INF=Float::INFINITY

H,W=get_i
Dir_=[[1,0],[-1,0],[0,-1],[0,1]]
$visit=array(W,false,H)
def bfs(s,r)
    que=[r]
    $visit[r[1]][r[0]]=true
    b=1
    w=0
    until que==[]
        p=que.shift
        Dir_.each do|x,y|
            nx=p[0]+x
            ny=p[1]+y
            next unless nx.between?(0,W-1) and ny.between?(0,H-1) and not $visit[ny][nx] and s[ny][nx]!=s[p[1]][p[0]]
            $visit[ny][nx]=true
            if s[ny][nx]=="#"
                b+=1
            else
                w+=1
            end
            que.push([nx,ny])
        end
    end
    return b,w
end
s=array(H)
H.times do|i|
    s[i]=get_nsp
end
ans=0
H.times do|i|
    W.times do|j|
        if not $visit[i][j] and s[i][j]=="#"
          b,w=bfs(s,[j,i])
          ans+=b*w
        end
    end
end
puts ans