/* -*- coding: utf-8 -*-
 *
 * 1903.cc:  No.1903 Day1 - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  // x=7q+r (r<7) -> n+6q=7q+r -> n=q+r

  int n;
  scanf("%d", &n);

  int r = min(n, 6), q = n - r;
  printf("%d\n", 7 * q + r);
  return 0;
}