#include<iostream>
#include <cstring>
using namespace std;
int main(){
    int a,c=0;
    cin>>a;
    for(int i=2;i<a;i++){
    	if(a%i==0){
    		c+=i;
		}
	}
	cout<<c;
    return 0;
}


/**************************************************************
	Problem: 1084
	User: xuanhua
	Language: C++
	Result: Time Limit Exceed
****************************************************************/