#include <atcoder/all>
using namespace atcoder;
// using mint = modint1000000007;
using mint = modint998244353;
// using mint = modint;//mint::set_mod(MOD);

// const long long MOD = 1000000007;
const long long MOD = 998244353;

#include <bits/stdc++.h>
#define rep(i, a, b) for (ll i = (ll)(a); i < (ll)(b); i++)
#define repeq(i, a, b) for (ll i = (ll)(a); i <= (ll)(b); i++)
#define repreq(i, a, b) for (ll i = (ll)(a); i >= (ll)(b); i--)
#define each(a, b) for (auto &(a) : (b))
#define endl '\n'  // fflush(stdout);
#define cYes cout << "Yes" << endl
#define cNo cout << "No" << endl
#define sortr(v) sort(v, greater<>())
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define tget(a, b) get<b>(a)
#define FI first
#define SE second
#define ALL(v) (v).begin(), (v).end()
#define INFLL 3000000000000000100LL
#define INF 1000000100
#define PI acos(-1.0L)
#define TAU (PI * 2.0L)

using namespace std;

typedef long long ll;
typedef pair<ll, ll> Pll;
typedef tuple<ll, ll, ll> Tlll;
typedef vector<int> Vi;
typedef vector<Vi> VVi;
typedef vector<ll> Vl;
typedef vector<Vl> VVl;
typedef vector<VVl> VVVl;
typedef vector<Tlll> VTlll;
typedef vector<mint> Vm;
typedef vector<Vm> VVm;
typedef vector<string> Vs;
typedef vector<double> Vd;
typedef vector<char> Vc;
typedef vector<bool> Vb;
typedef vector<Pll> VPll;
typedef priority_queue<ll> PQl;
typedef priority_queue<ll, vector<ll>, greater<ll>> PQlr;

/* print */
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &V) {
    int N = V.size();
    if (N == 0) {
        os << endl;
        return os;
    }
    rep(i, 0, N - 1) { os << V[i] << ' '; }
    os << V[N - 1] << endl;
    return os;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<vector<T>> &V) {
    int N = V.size();
    rep(i, 0, N) os << V[i];
    return os;
}
template <typename T, typename S>
ostream &operator<<(ostream &os, pair<T, S> const &P) {
    os << P.FI << ' ' << P.SE;
    return os;
}
ostream &operator<<(ostream &os, mint const &M) {
    os << M.val();
    return os;
}

/* useful */
template <typename T>
void Vin(vector<T> &v) {
    int n = v.size();
    rep(i, 0, n) cin >> v[i];
}
template <typename T>
int SMALLER(vector<T> &a, T x) {
    return lower_bound(a.begin(), a.end(), x) - a.begin();
}
template <typename T>
int orSMALLER(vector<T> &a, T x) {
    return upper_bound(a.begin(), a.end(), x) - a.begin();
}
template <typename T>
int BIGGER(vector<T> &a, T x) {
    return a.size() - orSMALLER(a, x);
}
template <typename T>
int orBIGGER(vector<T> &a, T x) {
    return a.size() - SMALLER(a, x);
}
template <typename T>
int COUNT(vector<T> &a, T x) {
    return upper_bound(ALL(a), x) - lower_bound(ALL(a), x);
}
template <typename T, typename S>
bool chmax(T &a, S b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <typename T, typename S>
bool chmin(T &a, S b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}
template <typename T>
void press(T &v) {
    v.erase(unique(ALL(v)), v.end());
}
template <typename T>
vector<int> zip(vector<T> b) {
    pair<T, int> p[b.size() + 10];
    int a = b.size();
    vector<int> l(a);
    for (int i = 0; i < a; i++) p[i] = mp(b[i], i);
    sort(p, p + a);
    int w = 0;
    for (int i = 0; i < a; i++) {
        if (i && p[i].first != p[i - 1].first) w++;
        l[p[i].second] = w;
    }
    return l;
}
template <typename T>
vector<T> vis(vector<T> &v) {
    vector<T> S(v.size() + 1);
    rep(i, 1, S.size()) S[i] += v[i - 1] + S[i - 1];
    return S;
}

ll dem(ll a, ll b) { return ((a + b - 1) / (b)); }
ll dtoll(double d, int g) { return round(d * pow(10, g)); }

const double EPS = 1e-10;

void init() {
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(12);
}

// do {} while (next_permutation(ALL(vec)));

/********************************** START **********************************/

void sol() {
    int n;
    cin >> n;
    cout << n * 2 - 1 << endl;
}

int main() {
    init();
    int q = 1;
    // cin >> q;
    while (q--) sol();
    return 0;
}