#pragma GCC optimize ("O2")
#pragma GCC target ("avx")
#include<bits/stdc++.h>
//#include<atcoder/all>
//using namespace atcoder;

using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define Would
#define you
#define please



int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


	ll K;
	cin >> K;

	if (K == 0) {
		co(1);
		return 0;
	}

	ll kotae = 2 * (K * (K - 1) + K * (K + 1)) + 2;
	co(kotae);

	Would you please return 0;
}