#include <bits/stdc++.h>
#include<iostream>
#include<map>
#include<vector>
#include <algorithm>
#include<math.h>
#include <iomanip>
#include<set>
#include <numeric>
#include<string>
using ll = long long;
using namespace std;

int main()
{
    ll n, sum1 = 0, i = 2, lim;
    cin >> n;
    lim = pow(n, 0.5);
    while (n>1 && i <= lim){
        if (!(n%i)){
            n /= i;
            lim = pow(n, 0.5);
            sum1 += i;
            continue;
        }
        i++;
    }
    if (n != 1) sum1 += n; 
    cout << sum1 << endl;
}