#include <bits/stdc++.h>

using namespace std;

long long  fir[1000001];

void pre()
{
    fir[1] = 1;
    long long po = 2;
    
    for(int i=2;i<=1000001;i++)
    {
        fir[i] = fir[i-1] + po;
        po+=2;
    }
    
}

long long sumOfGroup(long long k) {
    // Return the sum of the elements of the k'th group.
    
    long long ans = k*(fir[k] + fir[k+1]-2) /2;
    return ans;
    
    
    
    
}

int main() {
    pre();
    long long k;
    cin >> k;
    long long answer = sumOfGroup(k);
    cout << answer << endl;
    return 0;
}