Untitled

import java.util.Scanner;

public class P1 {
	public static int Sol(int n) {
		int sumValue = 1;

		for (int i = 2; i < n; i++) {
			if (n % i == 0) {
				sumValue += i;

				if (sumValue >= n) {
					sumValue -= i;
					break;
				}
			}
		}
		return sumValue;
	}

//	6 = 1, 2, 3, 6
// 8 = 1,2 ,4,8

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();

		System.out.println(Sol(n));
//		Sol(n);
	}
}