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);
        while (sc.hasNext()) {
            int num = sc.nextInt();
            if (num < 3) {
                System.out.println(-1);
                return;
            }
            int remainder = num % 4;
            switch (remainder) {
                case 0:
                    System.out.println(3);
                    break;
                case 2:
                    System.out.println(4);
                    break;
                default:
                    System.out.println(2);
            }
        }
    }
}