#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vvvvll = vector<vvvll>;
using vvvvvll = vector<vvvvll>;
using vvvvvvll = vector<vvvvvll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
using vvvvb = vector<vvvb>;
using vd = vector<double>;
using vvd = vector<vd>;
using vvvd = vector<vvd>;
using vvvvd = vector<vvvd>;
using vvvvvd = vector<vvvvd>;
#define all(A) A.begin(),A.end()
#define ALL(A) A.begin(),A.end()
#define rep(i, n) for (ll i = 0; i < (ll) (n); i++)
using pqr = priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>>;


template<class T>
bool chmax(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p < q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

template<class T>
bool chmin(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p > q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

ll gcd(ll(a), ll(b)) {
    if (a == 0)return b;
    if (b == 0)return a;
    ll c = a;
    while (a % b != 0) {
        c = a % b;
        a = b;
        b = c;
    }
    return b;
}
ll sqrtz(ll N) {
    ll L = 0;
    ll R = sqrt(N) + 10000;
    while (abs(R - L) > 1) {
        ll mid = (R + L) / 2;
        if (mid * mid <= N)L = mid;
        else R = mid;
    }
    return L;

}

template <typename T>
class ConvexHullTrick {
public:

    void add(T a, T b) {
        a = -a, b = -b;
        auto m = lines.insert({a, b, 0});
        auto l = m, r = m;
        ++r;
        while (update(m, r)) {
            r = lines.erase(r);
        }
        if (l != lines.begin() && update(--l, m)) {
            m = lines.erase(m);
            update(l, m);
        }
        m = l;
        while (l != lines.begin() && (--l)->p >= m->p) {
            update(l, lines.erase(m));
            m = l;
        }
    }

    T get(T x) const {
        assert(!lines.empty());
        auto it = *lines.lower_bound(x);
        return -(it.a * x + it.b);
    }

private:
    struct Line {
        mutable T a, b;  // ax + b
        mutable double p;  // intersection point with the next line
        bool operator<(const Line& o) const { return a < o.a; }
        bool operator<(T x) const { return p < x; }
    };

    using iterator = typename std::multiset<Line, std::less<>>::iterator;
    static constexpr double INF = std::numeric_limits<double>::max() / 2;

    std::multiset<Line, std::less<>> lines;

    bool update(iterator x, iterator y) const {
        if (y == lines.end()) {
            x->p = INF;
            return false;
        }
        if (x->a == y->a) {
            x->p = (x->b > y->b ? INF : -INF);
        } else {
            x->p = 1.0 * (y->b - x->b) / (x->a - y->a);
        }
        return x->p >= y->p;
    }
};

int main() {
    ll N,E,T;
   cin>>N;
   cout<<(2*N)-1<<endl;
}