#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

vector<pair<int,int>> p_fact(int N){
    vector<pair<int,int>> res;
    for(int p=2; p*p<=N; ++p){
        if(N % p != 0) continue;
        int ex = 0;
        while(N % p == 0){
            N /= p;
            ex++;
        }
        res.push_back({p,ex});
    }
    if(N != 1) res.push_back({N,1});
    return res;
}

int main(){
    int N;
    cin >> N;

    int ans = 0;
    if(N == 1){
        cout << ans << endl;
        return 0;
    }

    auto pf = p_fact(N);
    for(auto &[p,ex] : pf){
        rep(i, 0, ex) ans += p; 
    }
    cout << ans << endl;

    return 0;
}