#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  ll N; cin >> N;
  ll ans = 0;
  for(ll i = 1; i*i <= N; i++){
    if(N%i != 0) continue;
    if(i*i != N) ans += i;
    ans += N/i;
  }
  cout << ans << endl;
}