// 制約侵害 check

import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		new Main().run();
	}

	void run() {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		if (!(1 <= N && N <= 1e12))
			throw new AssertionError();
		long ans = 0;
		for (long i = 1; i * i <= N; ++i) {
			if (N % i == 0)
				ans += (i + (i == N / i ? 0 : N / i));
		}
		System.out.println(ans);
	}
}