#include<bits/stdc++.h>
using namespace std;
int n,s;
int main(){
	cin>>n;
	for(int i=2;i*i<=n;i++){
		if(i==n/i) s=s+i;
		else s=s+i+n/i; 
	
	}
	cout<<s;
} 
/**************************************************************
	Problem: 1084
	User: zhuanghaoxiang
	Language: C++
	Result: Wrong Answer
****************************************************************/