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 Python (3.4.3) (judge verdict: Accepted)

import sys
sys.setrecursionlimit(1000000)

h,w=map(int,input().split())
s=[input() for _ in range(h)]
t=[[None]*w for _ in range(h)]

def dfs(i,j,color):

  if not (0<=i<h and 0<=j<w):return 0,0
  if s[i][j]==color: return 0,0
  if t[i][j]:return 0,0

  t[i][j]=True
  wh,bl=0,0
  if s[i][j]=="#":
    bl+=1
  else:
    wh+=1

  tmp1,tmp2=dfs(i+1,j,s[i][j])
  wh,bl=wh+tmp1,bl+tmp2

  tmp1,tmp2=dfs(i-1,j,s[i][j])
  wh,bl=wh+tmp1,bl+tmp2
        
  tmp1,tmp2=dfs(i,j-1,s[i][j])
  wh,bl=wh+tmp1,bl+tmp2

  tmp1,tmp2=dfs(i,j+1,s[i][j])
  wh,bl=wh+tmp1,bl+tmp2

  return wh,bl

ans=0
for i in range(h):
  for j in range(w):
    a,b=dfs(i,j,"!")
    ans+=a*b

print(ans)