题意：求某点所在连通块的大小。
分析：由某点进行dfs，每次标记该点，并计数。
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N = 110, INF = 0x3f3f3f3f;
string s[N];
int n, m, d[][2] = {-1, 0, 0, 1, 1, 0, 0, -1};
int ans = 0;
void dfs(int x, int y) {
ans++, s[x][y] = '*';
for (int i = 0; i < 4; i++) {
int tx = x + d[i][0], ty = y + d[i][1];
if (tx < 0 || tx >= n || ty < 0 || ty >= m) continue;
if (s[tx][ty] != '.') continue;
dfs(tx, ty);
}
}
int main() {
while (cin >> m >> n && n) {
for (int i = 0; i < n; i++) cin >> s[i];
ans = 0;
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
if (s[i][j] == '@') dfs(i, j);
cout << ans << endl;
}
return 0;
}