#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES

#include <iostream>
#include <cstring>
#include <algorithm>
#include <limits.h>
#include <cmath>
#include <cstdio>
#include <vector>
#include <set>
#include <string>
#include <cstdlib>
#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;


int main(void)
{
  ll i,j,k,l;
  ll N;
  cin >> N;
  ll rep = 0;
  ll b = N;
  // もうN使わない
  vector<ll> c;
  if(b % 2 == 0) b /= 2;
  for(i=1;i*i<b;i++) {
    if(b % i == 0) {
      rep += i;
      // printf("rep += %llu\n",i);
      c.push_back(i);
    }
  }
  if(i*i == b) rep += i;
  for(i=0;i<c.size();i++) {
    // printf("c[%d] = %d\n",i,c[i]);
    rep = rep + b/(c[i]);
   //  printf("rep += %llu\n",b/c[i]);
  }
  cout << rep << endl;
  return 0;
}