#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; ++i)
typedef long long int_t;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;

    rep (i, n) {
        if (i % 7 == 6) n += 6;
    }

    cout << n << endl;

    return 0;
}