#include<stdio.h>
#include<math.h>
#include<algorithm>
using namespace std;

#define inf 1999888777
#define eps 0.000001
#define pi 3.14159265358979


int main() {

     int n,i,res;
     scanf("%d", &n);
     res=0;
     for(i=2; i<n; i++) {

     	while(n%i==0) {
     		res+=i-1;
     		n/=i;
     	}

     }

     res+=n-1;
     printf("%d\n", res);

     return 0;
}