求助!样例全都过不去

#include <bits/stdc++.h>
using namespace std;
char a[10005][10005];
int main(){
	long long n, m, ans = 0;
	scanf("%lld %lld", &n, &m);
	for(long long i = 2; i <= n + 1; i++) for(long long j = 2; j <= m + 1; j++) cin >> a[i][j];
	for(long long i = 2; i <= n + 1; i++){
		for(long long j = 2; j <= m + 1; j++){
			if(a[i][j] == 'h'){
				if(a[i - 1][j] == 'e' && a[i - 2][j] == 'h' && a[i - 3][j] == 'e') ans++;
				if(a[i][j - 1] == 'e' && a[i][j - 2] == 'h' && a[i][j - 3] == 'e') ans++;
				if(a[i + 1][j] == 'e' && a[i + 2][j] == 'h' && a[i + 3][j] == 'e') ans++;
				if(a[i][j + 1] == 'e' && a[i][j - 2] == 'h' && a[i][j - 3] == 'e') ans++;
			}
		}
	}
	printf("%lld", ans);
	return 0;
}