题解 | #杨辉三角的变形#

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.time.LocalDateTime;
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.Stream;

import static java.util.stream.Stream.*;


public class Main {
    public static void main(String[] args) throws IOException {

       //testCompletePack();
        testTh();
    }

    private static void testTh() throws IOException {
        BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));
        String str;
        while ((str=bf.readLine())!=null){
            int parseInt = Integer.parseInt(str);
            if (parseInt<=2) {
                 System.out.println(-1);
                 break;
            }
           
            int i = (parseInt - 2) % 4;
            if (i==1){
                System.out.println(2);
            } else if (i==2) {
                System.out.println(3);
            }else if (i==3){
                System.out.println(2);
            }else {
                System.out.println(4);
            }
        }

    }
}