pku1979

#include < stdio.h >
#include < stdlib.h >
#include < string .h >
int  visited[ 100 ][ 100 ];
char  str[ 100 ][ 100 ];
int  i,j,n,m,move[ 4 ][ 2 ] = {{ 0 , 1 },{ 0 , - 1 },{ 1 , 0 },{ - 1 , 0 }},count,max;
int  f( int  x, int  y)
{
     if (x >= 0 && y >= 0 && x < n && y < m)
         return   1 ;
     else  
         return   0 ;
}
void  dfs( int  i, int  j)
{
     int  k,x = i,y = j;

     if (str[x][y] == ' . ' && f(x,y))
    {
         ++ count;
        

    visited[x][y] = 1 ;

         for (k = 0 ;k < 4 ;k ++ )
        {   

         x = i + move[k][ 0 ];y = j + move[k][ 1 ];
            if (str[x][y] == ' . ' && f(x,y) && ( ! visited[x][y]))
            
            dfs(x,y);
        }
    }
}
int  main()
{
     int  x = 0 ,y = 0 ,i,j;
    
     while (scanf( " %d %d " , & m, & n))
    {
         if (n == 0 && m == 0 )
             break ;
        memset(str, 0 , sizeof (str));
         for (i = 0 ;i < n;i ++ )
            scanf( " %s " ,str[i]);
        count = 0 ;
         for (i = 0 ;i < n;i ++ )
             for (j = 0 ;j < m;j ++ )
            {
                 if (str[i][j] == ' @ ' )
                {
                    x = i;y = j;
            
                }
                visited[i][j] = 0 ;
            }
            str[x][y] = ' . ' ;
         
            dfs(x,y);
            printf( " %d\n " ,count);
            memset(visited, 0 , sizeof (visited));


    }
     // system("pause");
    
     return   0 ;
        
}