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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using static System.Math;
using static System.Array;
using static AtCoder.Tool;

namespace AtCoder
{
    class AC
    {
        const int MOD = 1000000007;
        const int INF = int.MaxValue / 2;
        const long SINF = long.MaxValue / 2;
        const double EPS = 1e-8;
        static readonly int[] dx = { 0, 1, 0, -1 };
        static readonly int[] dy = { 1, 0, -1, 0 };
        //static List<List<int>> G = new List<List<int>>();
        //static List<List<Edge>>G = new List<List<Edge>>();
        //static List<Edge> E = new List<Edge>();
        static char[,] map;
        static bool[,] used;
        static long bl, wh;
        
        static void Main(string[] args)
        {
            //var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            //Console.SetOut(sw);
            var cin = new Scanner();
            var input = cin.SplitRead();
            int H = input[0];
            int W = input[1];

            used = new bool[H + 2, W + 2];
            map = new char[H + 2, W + 2];
            for(var i = 0; i < H + 2; i++)
            {
                if (i == 0 || i == H + 1)
                {
                    for (var j = 0; j < W + 2; j++) { map[i, j] = '@';used[i, j] = true; }
                }
                else
                {
                    var s = Console.ReadLine();
                    for(var j = 0; j < W + 2; j++)
                    {
                        map[i, j] = (j == 0 || j == W + 1) ? '@' : s[j - 1];
                        used[i, j] = (j == 0 || j == W + 1);
                    }
                }
            }

            long ans = 0;
            for(var i = 1; i <= H; i++)
            {
                for(var j = 1; j <= W; j++)
                {
                    if (used[i, j]) { continue; }
                    Dfs(i, j);
                    ans += bl * wh;
                    //Console.WriteLine($"{bl} {wh}");
                    bl = 0;wh = 0;
                }
            }

            Console.WriteLine(ans);


            /*for(var i = 0; i < H + 2; i++)
            {
                for(var j = 0; j < W + 2; j++)
                {
                    Console.Write($"{map[i, j]} ");
                }
                Console.WriteLine();
            }*/
            //Console.Out.Flush();
        }
        static public void Dfs(int y, int x)
        {
            used[y, x] = true;
            for(var k = 0; k < 4; k++)
            {
                int ny = y + dy[k];
                int nx = x + dx[k];
                if (used[ny, nx] || map[ny, nx] == '@') { continue; }
                if (map[y, x] == map[ny, nx]) { continue; }
                Dfs(ny, nx);
            }
            if (map[y, x] == '#') bl++;
            else wh++;
        }

        struct Edge
        {
            public int from;

            public int to;
            public long dist;
            public Edge(int t, long c)
            {
                from = -1;
                to = t;
                dist = c;
            }
            public Edge(int f, int t, long c)
            {
                from = f;
                to = t;
                dist = c;
            }

        }
        struct Pair<T, U> : IComparable<Pair<T, U>>
        where T : IComparable<T>
        where U : IComparable<U>
        {
            public T first;
            public U second;
            private readonly bool CompWithFirst;

            public Pair(T f, U s, int comp)
            {
                first = f;
                second = s;
                CompWithFirst = comp == 1;
            }
            public Pair(T f,U s)
            {
                first = f;
                second = s;
                CompWithFirst = true;
            }

            public int CompareTo(Pair<T, U> other)
            {
                return CompWithFirst ? first.CompareTo(other.first) : second.CompareTo(other.second);
            }
        }
    }
    public class PriorityQueue<T> where T : IComparable<T>
    {

        private List<T> Q;
        private readonly int r;

        public PriorityQueue(bool ascending)
        {
            if (ascending)
            {
                r = 1;
            }
            else
            {
                r = -1;
            }
            Q = new List<T>();
        }


        private void PushHeap(List<T> list, T item)
        {
            int n = list.Count();
            list.Add(item);

            while (n != 0)
            {
                int pIndex = (n - 1) / 2;

                if (list[n].CompareTo(list[pIndex]) * r > 0)
                {
                    Swap(Q, n, pIndex);
                }
                else { break; }

                n = pIndex;
            }
        }

        private void PopHeap(List<T> list)
        {
            int n = list.Count() - 1;
            list[0] = list[n];
            list.RemoveAt(n);

            int cur = 0;
            int comp;

            while (2 * cur + 1 <= n - 1)
            {
                int c1 = 2 * cur + 1;
                int c2 = 2 * (cur + 1);
                if (c1 == n - 1)
                {
                    comp = c1;
                }
                else
                {

                    comp = list[c1].CompareTo(list[c2]) * r > 0 ? c1 : c2;
                }

                if (list[cur].CompareTo(list[comp]) * r < 0)
                {
                    Swap(Q, cur, comp);
                }
                else { break; }

                cur = comp;
            }
        }

        private void Swap(List<T> list, int a, int b)
        {
            T keep = list[a];
            list[a] = list[b];
            list[b] = keep;
        }



        public void Enqueue(T value)
        {
            PushHeap(Q, value);
        }

        public T Dequeue()
        {
            T ret = Q[0];
            PopHeap(Q);
            return ret;
        }

        public T Peek()
        {
            return Q[0];
        }

        public int CountItem()
        {
            return Q.Count();
        }
    }
    public class Scanner
    {
        public int[] SplitRead()
        {
            int[] array = Console.ReadLine().Split().Select(int.Parse).ToArray();
            return array;
        }
        public long[] SplitReadL()
        {
            long[] array = Console.ReadLine().Split().Select(long.Parse).ToArray();
            return array;
        }
    }
    public static class Tool
    {
        static public void Initialize<T>(ref T[] array, T initialvalue)
        {
            for (var i = 0; i < array.Length; i++)
            {
                array[i] = initialvalue;
            }
        }

        static public T MaxLot<T>(params T[] val) where T : IComparable<T>
        {
            T ret = val[0];
            for (var i = 1; i < val.Count(); i++)
            {
                if (ret.CompareTo(val[i]) < 0) { ret = val[i]; }
            }
            return ret;
        }
        static public T MinLot<T>(params T[] val) where T : IComparable<T>
        {
            T ret = val[0];
            for (var i = 1; i < val.Count(); i++)
            {
                if (ret.CompareTo(val[i]) > 0) { ret = val[i]; }
            }
            return ret;
        }
    }

}