import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		long sum = 0;
		for (long idx = 1; idx <= Math.sqrt(n); idx++) {
		    if (n % idx == 0) {
		        sum += idx;
		        if (idx != n / idx) {
		            sum += n / idx;
		        }
		    }
		}
		System.out.println(sum);
	}
}