题解 | #杨辉三角的变形#

#include<iostream>
using namespace std;
int main(){
	int n;
	cin >> n;
	if (n <= 2){
		cout << "-1";
	}
	else if((n-3)%4==0||(n-3)%4==2){
		cout << "2";
	}
	else if((n-3)%4==1){
		cout << "3";
	}
	else{
		cout << "4";
	}
}