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

int main(){
    long int n;
    long int i;
    long int z = 0;
    cin >> n;
   
   z += ( n / 3 ) * 2;
   z += ( n / 5 ) * 2;
   
    cout << z << endl;
    
    return 0;
}