guIT

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

int main()
{
    long long n, d=2, S=0, p;
    cin>>n;
    while(n>1){
        p=0;
        while(n%d==0){
            n/=d;
            p++;
        }
        if(p>0){
            S+=d;
        }
        d++;
    }
    cout<<S;
    return 0;
}