// https://www.hackerrank.com/challenges/java-interface/problem?h_r=next-challenge&h_v=zen&h_r=next-challenge&h_v=zen&h_r=next-challenge&h_v=zen&h_r=next-challenge&h_v=zen

import java.util.Scanner;

public class JavaInterface {

public static void main(String[] args) {

MyCalculator my_calculator = new MyCalculator();

System.out.print("I implemented: ");

ImplementedInterfaceNames(my_calculator);

Scanner scanner = new Scanner(System.in);

int n = scanner.nextInt();

System.out.print(my_calculator.divisor_sum(n) + "\n");

scanner.close();

}

private static void ImplementedInterfaceNames(Object o){

Class[] theInterfaces = o.getClass().getInterfaces();

for (int i = 0; i < theInterfaces.length; i++){

String interfaceName = theInterfaces[i].getName();

System.out.println(interfaceName);

}

}

}

interface AdvancedArithmetic {

int divisor_sum(int number);

}

class MyCalculator implements AdvancedArithmetic {

@Override

public int divisor_sum(int number) {

int result = 1 + (number > 1 ? number : 0);

for (int index = 2 ; index < number ; index++) {

result += number % index == 0 ? index : 0 ;

}

return result;

}

}