求助，样例全过但0分（玄关）

#include <iostream>
#include <cmath>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#define LL long long
using namespace std;

LL x, y;
char a[501][501];
LL ans = 0;

int main() {
	cin >> x >> y;
	for (int i = 1; i <= x; i++) {
		for (int j = 1; j <= y; j++) {
			cin >> a[i][j];
		}
	}
	for (int i = 1; i <= x; i++) {
		for (int j = 1; j <= y; j++) {
			if (a[i][j] == '0' && i != 1 && j != 1 && i != x && j != y) {
				if (a[i + 1][j] == '*' && a[i][j + 1] == '*' && a[i][j - 1] == '*' && a[i - 1][j] == '*') {
					ans++;
				}
			}
		}
	}

	cout << ans;

	return 0;
}