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

int main()
{
    long N;
    cin >> N;

    long bai3,bai5,bai15;
    bai3 = N / 3;
    bai5 = N / 5;
    bai15 = N / 15;

    cout << (bai3-bai15)*2 + (bai5-bai15)*2 + bai15*4 <<endl;

    return 0;
}