#include <iostream>
#include "math.h"
using namespace std;
int main() {
    // insert code here...
    double n;
    double threeNum,fiveNum;
    double fifteenNum;
    cin >> n;
    
    fifteenNum = floor(n/15);
    threeNum = floor(n/3) -fifteenNum;
    fiveNum = floor(n/5) -fifteenNum;
    
    double ans = 4 * fifteenNum + 2 * (threeNum + fiveNum);
    cout.precision(18);
    cout << ans <<endl;
    

    return 0;
}