#include<bits/stdc++.h>
using namespace std;
long long n;
int main(){
    freopen("hs.in","r",stdin);
    freopen("hs.out","w",stdout);
    cin>>n;
    int sum=0;
    int i=2;
    if(n==1){
        cout<<1;
        return 0;
    }
    while(n){
        if(n==i){
            sum+=i;
            break;
        }
        if(n%i==0){
            n/=i;
            sum+=i;
        }
        else{
            i++;
        }
    }
    cout<<sum;
    return 0;
}