#include <iostream>
using namespace std;

unsigned long long T[1001000];

int main() {
    T[1] = 1;
    unsigned long long curr = 1, incr = 4;
    for(int i=2; i<=1000000; i++) {
        curr += incr;
        //cout << " " << T[i-1] << " " << (i-1) * incr << " " << curr << endl;
        T[i] = T[i-1] + (i-1) * (incr-2) + curr;
        incr += 2;
    }
    
    int K;
    while(cin >> K) {
        cout << T[K] << endl;
    }
}