import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); long n = sc.nextLong(); long ans = 0; if((n % 2) == 0) { n /= 2; } else { } for(long i = 1; (i * i) <= n; i++) { if((n % i) == 0) { long t = n / i; ans += (i + t); } } System.out.println(ans); } }