#include <bits/stdc++.h>

using namespace std;

#define ll long long;
const int scz = 1e9;

int main()
{
    ///freopen ("sapsan.in", "r", stdin);
    ///freopen ("sapsan.out", "w", stdout);
    int n;
    cin >> n;
    for (int i = n; i >= 0; i -= 2)
    {
        if ((i / 2) % 2 == 0 && (i / 2) + ((i / 2) / 2) <= n / 2)
        {
            cout << i;
            return 0;
        }
    }
}