#include <iostream>
#include <string>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;

long long a[] = {0, 0, 0, 2, 2, 4, 6, 6, 6, 8, 10, 10, 12, 12, 12};
int main(void)
{
    long long N;
    cin >> N;
    long long base = 16;

    cout << N / 15 * base + a[N % 15] << endl;
    return 0;
}