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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Numerics;
using System.IO;
using System.Runtime.InteropServices;
using static System.Math;
using static Math2;
using static io;
using static Utils;



public class CompetitiveProgramming
{
  int[] delta = new int[] { 1, 0, -1, 0, 1 };
  public void Solve()
  {
    var o = Ints;
    var H = o[0];
    var W = o[1];
    var S = new char[H][];
    for (int i = 0; i < H; ++i) S[i] = Chars;
    var uf = new UnionFind(H * W);
    for (int i = 0; i < H; ++i)
    {
      for (int j = 0; j < W; ++j)
      {
        int cs = 0;
        if (S[i][j] == '#') cs = 1;
        for (int k = 0; k < 4; ++k)
        {
          int dx = i + delta[k];
          int dy = j + delta[k + 1];
          if (dx < 0 || dx >= H || dy < 0 || dy >= W) continue;
          int cs2 = 0;
          if (S[dx][dy] == '#') cs2 = 1;
          if ((cs ^ cs2) == 1)
          {
            uf.Merge(i * W + j, dx * W + dy);
          }
        }
      }
    }

    var cntblack = new int[H * W];
    var cntwhite = new int[H * W];
    for (int i = 0; i < H; ++i)
    {
      for (int j = 0; j < W; ++j)
      {
        var curconnect = uf.GetParent(i * W + j);
        if (S[i][j] == '#') ++cntblack[curconnect];
        else ++cntwhite[curconnect];
      }
    }
    long ans = 0;
    for (int i = 0; i < H * W; ++i)
    {
      ans += cntwhite[i] * cntblack[i];
    }
    Write(ans);


  }

}
public class UnionFind
{
  int _count;
  int[] par, sizes, rank;
  public UnionFind(int N)
  {
    _count = N;
    par = new int[N];
    sizes = new int[N];
    rank = new int[N];
    for (int i = 0; i < N; ++i)
    {
      par[i] = i;
      sizes[i] = 1;
      rank[i] = 0;
    }
  }
  int Root(int X)
  {
    if (par[X] == X)
    {
      return X;
    }
    else return (par[X] = Root(par[X]));
  }
  public bool Merge(int X, int Y)
  {
    X = Root(X);
    Y = Root(Y);
    if (X == Y) return false;
    --_count;
    if (rank[X] < rank[Y])
    {
      par[X] = Y;
      sizes[Y] += sizes[X];
    }
    else
    {
      par[Y] = X;
      sizes[X] += sizes[Y];
      if (rank[X] == rank[Y]) ++rank[X];
    }
    return true;
  }
  public bool IsSame(int X, int Y) => Root(X) == Root(Y);
  public int Count => _count;
  public bool IsParent(int X) => X == Root(X);
  public int GetParent(int X) => Root(X);
  public int Size(int X) => sizes[Root(X)];
}

public static class Math2
{
  public const int INF = 1 << 29;
  public const long INFL = 1L << 60;
  public const long MOD = 1000000007;
  public const int MOD2 = 998244353;

  public static long Power(long a, long b, long MOD = 1000000007)//i^N
  {
    long res = 1;
    while (b > 0)
    {
      if ((b & 1) != 0) res = res * a % MOD;
      a = a * a % MOD;
      b >>= 1;
    }
    return res;
  }
  public static long Power2(long a, long b)//i^N
  {
    long res = 1;
    while (b > 0)
    {
      if ((b & 1) != 0) res = res * a;
      a = a * a;
      b >>= 1;
    }
    return res;
  }
  public static long GCD(long a, long b)
  {
    while (b > 0)
    {
      var r = a % b;
      a = b;
      b = r;
    }
    return a;
  }
  public static long LCM(long a, long b) => (b / GCD(a, b)) * a;
  public static long Comb(long n, long r, int MOD = 1000000007)
  {
    long ret = 1;
    long x = 1;
    for (long i = n; i >= n - r + 1; --i)
    {
      ret = ret / x * i;
      ret %= MOD;
      x++;
    }
    return ret;
  }
  public static long Comb2(long n, long r)
  {
    long Nume = 1;
    long Deno = 1;

    if (r > n - r) r = n - r;
    for (long i = 1; i <= r; ++i)
    {
      Deno *= i;
      Nume *= n - i + 1;
    }
    return Nume / Deno;
  }
}
public static class Utils
{

  public static void Swap<T>(ref T A, ref T B)
  {
    T x = A;
    A = B;
    B = x;
  }
  public static int DigitSum(int N)
  {
    string s = N.ToString();
    int ret = 0;
    for (int i = 0; i < s.Length; ++i) ret += s[i] - '0';
    return ret;
  }
}
class Program
{
  static void Main(string[] args)
  {
    var CompetitiveProgramming = new CompetitiveProgramming();
    CompetitiveProgramming.Solve();
  }
}
public static class io
{
  public static string Str => Console.ReadLine();
  public static string[] Strs => Str.Split(' ');
  public static long[] Longs => Strs.Select(long.Parse).ToArray();
  public static int[] Ints => Strs.Select(int.Parse).ToArray();
  public static char[] Chars => Str.ToArray();
  public static double[] Doubles => Strs.Select(double.Parse).ToArray();
  public static long Long1 => Longs[0];
  public static int Int1 => Ints[0];
  public static char Char1 => Chars[0];
  public static double Double1 => Doubles[0];
  public static long[] VerticalRead(int N) { long[] A = new long[N]; for (int i = 0; i < N; ++i) A[i] = Long1; return A; }
  public static void Write(string a) => Console.WriteLine(a);
  public static void Write(params object[] i) => Write(string.Join(" ", i));
  //public static void Write<T>(IEnumerable<T> a) => Write(string.Join(" ", a));
  public static void Verticalwrite<T>(IEnumerable<T> a) { foreach (var z in a) Write(z); }
  public static void YN(bool i) { if (i) Write("Yes"); else Write("No"); }
}