#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
typedef long long ll;
using namespace std;

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int A;
    cin >> A;
    cout << 2 * A - 1 << "\n";

    return 0;
}