请各位大佬看一看，蒟蒻的代码哪里错了：

#include <bits/stdc++.h>
using namespace std;
long long n,ans;
struct student {
	string name;
	int ch,ma,en,sum;//创建结构体
};

student a[10001];

bool cmp(student x,student y) {
	return x.name<y.name;//比较
}
int main() {
	cin>>n;
	for (int i=1;i<=n;i++) {
		cin>>a[i].name>>a[i].ch>>a[i].ma>>a[i].en;
		a[i].sum=a[i].ch+a[i].ma+a[i].en;
	}
	sort (a+1,a+n+1,cmp);
	for (int i=1;i<n;i++) {
		for (int j=i+1;j<=n;j++) {
			if (abs(a[i].ch-a[j].ch)<=5 && abs(a[i].ma-a[j].ma)<=5 && abs(a[i].en-a[j].en)<=5 && abs(a[i].sum-a[j].sum)<=10) {//进行操作
				ans++;
			}
 		}
	}
   cout<<ans;
	return 0;
}