#include <bits/stdc++.h>
using namespace std;

int main()
{
    int N;
    cin >> N;
    int ans = 0;
    int i = 1;
    while (N > 0)
    {
        if (i % 7 == 0)
        {
            N += 6;
        }
        ans++;
        N--;
        i++;
    }
    cout << ans;
}