[백준] 2839 설탕문제 Java

import java.util.Scanner;
 
public class Main {
     
    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int five = 0;
        int three = 0;
        
        
        while(N%5!=0&&N>=0){
            N-=3;
            three++;
        }
        if(N<0){
            System.out.println(-1);
        }
        else{
            five = N/5;
            System.out.println(five+three);        
        }
    
    }
 
}