WA了 求

#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll n;
int main(){
	while(true){
		cin>>n;
		if(n==0 || n==1){
			cout<<1;
			return 0;
		}
		cout<<(n*n*n*n-6*n*n*n+23*n*n-18*n)/24+1<<endl;
	}
	return 0;
}