#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int N;
  cin>>N;
  int ans = 0;
  int n = N;
  for(int i=2;i<=n;i++){
      while(N%i == 0){
          N /= i;
          ans += i;
      }
  }
  cout<<ans<<endl;
}