HDU 1312

#include<stdio.h>
#include<string.h>
char str[22][22];
int temp[22][22];
int cnt,h,w;
void dfs(int x,int y)
{
    cnt ++;
    temp[x][y] = 1;
    if(!temp[x+1][y]&& x+1 < w)
        dfs(x+1,y);
    if(!temp[x-1][y] && x-1 > -1)
        dfs(x-1,y);
    if(!temp[x][y+1] && y+1 < h)
        dfs(x,y+1);
    if(!temp[x][y-1] && y-1 > -1)
        dfs(x,y-1);
}

int main()
{
    int i,j,a,b;
    while(~scanf("%d%d",&h,&w)&&h+w)
    {
        cnt = 0;
        for(i = 0;i < w;i ++)
        {
            scanf("%s",str[i]);
            for(j = 0;j < h;j ++)
            {
                if(str[i][j] == '#')
                    temp[i][j] = 1;
                if(str[i][j] == '.')
                    temp[i][j] = 0;
                if(str[i][j] == '@')
                {
                    a = i;
                    b = j;
                }
            }
        }
        dfs(a,b);
        printf("%d\n",cnt);
    }
    return 0;
}