#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int N, i=1;
    cin >> N;

    while(1){
        if (i % 7 == 0) N+=6;
        N--;
        if (N == 0) break;
        i++;
    }

    cout << i << endl;

    return 0;
}