9506번 약수들의 합

import java.util.*;
class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        while(true){
            int n = sc.nextInt();
            if(n == -1){
                break;
            }
            
            int sum = 0;
            StringBuilder str = new StringBuilder(); 
            for(int i = 1 ; i < n ; i++){
                if(n%i == 0){
                    sum+=i;
                    str.append(i).append(" + "); //1 + ~~
                }
            }
            
            if(sum==n){
                str.setLength(str.length() - 3); 
                System.out.println(n + " = " + str); 
            }else{
                System.out.println(n + " is NOT perfect.");
            }
        }
    }
}