题解 | #杨辉三角的变形#

import java.util.*;


public class Main{
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        int m = sc.nextInt();//行数
        if(m<3){
            System.out.println(-1);
        }else if(m % 2 == 1){
            System.out.println(2);
        }else if(m %4 == 0){
            System.out.println(3);
        }else if(m %4 == 2){
            System.out.println(4);
        }
      
      
    }
}