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

    return 0;
}