#include <iostream>
#include <vector>
using namespace std;

struct PrimeDecomposition
{
    int n;
    vector<bool> p;
    vector<int> prime;
    vector<int> d;
    
    PrimeDecomposition(int n) : n(n){
        p.resize(n + 1);
        d.resize(n + 1);
        d[1] = 1;
        for(int i = 2; i <= n; i++){
            if(!p[i]){
                prime.push_back(i);
                for(int j = i; j <= n; j += i){
                    if(!p[j]) d[j] = i;
                    p[j] = true;
                }
            }
        }
    }
    
    vector<int> decomposition(int x){
        vector<int> res;
        while(x > 1){
            res.push_back(d[x]);
            x /= d[x];
        }
        return res;
    }
};

int main()
{
    int n;
    cin >> n;
    PrimeDecomposition pd(n);
    vector<int> v = pd.decomposition(n);
    int ans = 0;
    for(int i : v) ans += i;
    cout << ans << endl;
}