package main

import . "fmt"

func main() {
	var n,s int64
	Scan(&n)
	for i:=int64(1); i*i<=n; i++ {
		if n%i != 0 {
			continue
		}
		s += i + n/i
		if i*i == n {
			s -= i
		}
	}
	Println(s)
}