#include <bits/stdc++.h>
using namespace std;
using ll=long long;

int main()
{
  ll n;
  cin>>n;
  ll s=0;
  for(ll i=1;i*i<=n;++i){
    if(n%i==0){
      s+=i;
      s+=n/i;
    }
    if(i*i==n){
      s-=i;
    }
  }
  cout<<s<<endl;
}