#include<iostream>
#include<map>
#include<algorithm>
#include <iomanip>
#include <cmath>
#include <sstream>
#include <unordered_map>
#include <unordered_set>
#include <deque>
#include <vector>
#include <bitset>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <cstring>

#define INF 1050000000
#define MOD 1000000007

using namespace std;



int main() {
	long long int n; cin >> n;
	cout << 1 + (n - 1) * 2 << endl;







}