题解 | #杨辉三角的变形#

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