#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = s; i < (t); ++i)
#define dsrep(i, t, s) for (int i = (t)-1; i >= (s); --i)
#define rng(a) a.begin(), a.end()
#define rrng(a) a.rbegin(), a.rend()
#define isin(x, l, r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define eb emplace_back
#define sz(x) (int)(x).size()
using namespace std;
using ll = long long;
template <typename T>
using vc = vector<T>;
template <typename T>
using vv = vc<vc<T>>;
template <typename T>
using vv = vc<vc<T>>;
using vl = vc<ll>;
using vvl = vv<ll>;
using vvvl = vv<vl>;
typedef pair<int, int> P;
const int INF = 1001001001;
const ll LINF = 1001002003004005006ll;
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};

int main() {
  ll a;
  cin >> a;
  cout << 2 * a - 1 << endl;
}