#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;
using ll = long long;
int main() {
  int n;
  cin >> n;
  int m = 0, ans = 0;
  vector<int> t = {2, 2, -1, -1, 2, -1, -1};
  int cnt = 0;
  while(m != n) {
    m += t[cnt];
    ans += abs(t[cnt]);
    cnt++;
    cnt %= 7;
  }
  cout << ans << endl;
  return 0;
}