#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;

using Pair = pair<int, int>;
using Tuple = tuple<int, int, int>;
using VI1 = vector<int>;
using VI2 = vector<VI1>;
using VL1 = vector<ll>;
using VL2 = vector<VL1>;
using VD1 = vector<ld>;
using VD2 = vector<VD1>;
using VB1 = vector<bool>;
using VB2 = vector<VB1>;
using VP1 = vector<Pair>;
using VP2 = vector<VP1>;
using VT1 = vector<Tuple>;
using VT2 = vector<VT1>;

using Queue = queue<int>;
using DQ = deque<int>;
using PQ = priority_queue<int, vector<int>, greater<int>>;
using Table = VI2;
using Graph = VI2;

auto solve() {
  ll A;
  cin >> A;
  return 2 * A - 1;
}

int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  auto result = solve();
  cout << result << endl;
}