#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ff(i,a,b) for(ll i=a;i<=b;i++)
int32_t main(){
    ll n,res = 1;
    cin>>n;
    while(n != 0){
        if (res%7 == 0) n += 6;
        res++;
        n--;
    }
    cout<<res-1;
}