> #include "stdio.h"
> #include "memory.h"
> 
> const int M = 10000;
> class queue
> {
> public:
> 	int x[M];
> 	int y[M];
> 	int head,tail;
> 	queue(){head=0;tail=0;}
> 	void inqueue(int tx,int ty)
> 	{
> 		x[tail]=tx;
> 		y[tail]=ty;
> 		tail++;
> 	}
> 	void dequeue(int &tx,int &ty)
> 	{
> 		tx=x[head];
> 		ty=y[head];
> 		head++;
> 	}
> }q;
> 
> char a[90][110];
> bool used[90][110];
> int rel ,m ;
> int w,h;
> 
> void solve(int tx, int ty)
> {
> 	int x, y;
> 	m = 0 ;
> 	q.head = 0 ;
> 	q.tail = 0 ;
> 	q.inqueue( tx, ty);
> 	m ++ ;
> 	used[tx][ty] = 1;
> 	while(1)
> 	{
> 		if( q.tail > q.head )
> 			q.dequeue( x, y);
> 		else
> 		{
> 			rel = rel > m ? rel : m ;
> 			break;
> 		}
> 		if( x >= 0 && x < h && y >=0 && y < w )
> 		{
> 			if( x-1 >= 0 && x-1 < h && y >=0 && y< w &&a[x-1][y] == '*'&& used[x-1][y]==0)
> 			{
> 				q.inqueue( x - 1, y);
> 				m ++ ;
> 				used[x-1][y] = 1;
> 			}
> 			if(x+1 >= 0 && x+1 < h && y >=0 && y < w && a[x+1][y] == '*'&& used[x+1][y]==0)
> 			{
> 				q.inqueue( x+1, y );
> 				m ++ ;
> 				used[x+1][y] = 1;
> 			}
> 			if( x >= 0 && x < h && y-1 >=0 && y-1 < w  && a[x][y-1] == '*'&& used[x][y-1]==0)
> 			{
> 				q.inqueue( x , y - 1);
> 				m ++ ;
> 				used[x][y-1] = 1;
> 			}
> 			if( x >= 0 && x < h && y+1 >=0 && y +1< w && a[x][y+1] == '*'&& used[x][y+1]==0)
> 			{
> 				q.inqueue( x , y + 1);
> 				m ++ ;
> 				used[x][y+1] = 1;
> 			}
> 		}
> 
> 	}
> }
> 
> int main()
> {
> 	while( scanf( "%d%d", &w,&h) != EOF )
> 	{
> 		int i,j;
> 		for( i = 0 ; i < h ; i ++ )
> 		{
> 			scanf( "%s", a[i]);
> 			memset( used[i] , 0 , 110 * sizeof(bool));
> 		}
> 		rel = 0 ;
> 		for( i = 0 ; i < h ; i ++ )
> 			for( j = 0 ; j < w ; j ++)
> 			{
> 				if( a[i][j] == '*' && used[i][j] == 0 )
> 					solve(i,j);			
> 			}
> 		printf( "%d\n", rel);
> 	}
> 	return 0;
> }
> 
> 
> /*
> 10 5
> ..*.....**
> .**..*****
> .*........
> ..****.***
> ..****.***
> 
> 10 5
> ..........
> ..........
> ..........
> ..........
> ..........
> 
> 10 5
> **********
> **********
> **********
> **********
> **********
> 
> 10 5
> *.*.*.*.*.
> .*.*.*.*.*
> *.*.*.*.*.
> .*.*.*.*.*
> *.*.*.*.*.
> */