#include<cstdio>
#include<cstring>
#include<iostream>
#include<cmath>
#include<ctime>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<stack>
#include<map>
using namespace std;
typedef long long LL;
const int MR=1e6+10;
int n;
int main(){
    cin>>n;
    int ans=0;
    for(int i=2;i*i<=n;i++){
        if(n%i!=0) continue;
        while(n%i==0){
            ans+=i;
            n/=i;
        }
    }
    if(n>1) ans+=n;
    cout<<ans<<endl;
    return 0;
}