#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second

const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll INF = 1LL << 60;
const ll N_MAX = 2e5;

int main(){
    ll x;
    cin >> x;

    ll ans = 0;
    ll now = 0;
    while(true){
        now += 2;
        ans += 2;
        if(now == x) break;
        now += 2;
        ans += 2;
        if(now == x) break;
        now -= 1;
        ans += 1;
        if(now == x) break;
        now -= 1;
        ans += 1;
        if(now == x) break;
        now += 2;
        ans += 2;
        if(now == x) break;
        now -= 1;
        ans += 1;
        if(now == x) break;
        now -= 1;
        ans += 1;
        if(now == x) break;
    }

    cout << ans << endl;
}