#include <bits/stdc++.h>

using namespace std;

long sumOfGroup(int k) {
    // Return the sum of the elements of the k'th group.
    int temp=k;
    long int sum=k;
    while(k>0)
    {
        k--;
        sum+=k;
    }
    long int total=0;
    for(int i=temp;i>0;i--)
    {
        total+=2*sum-1;
        sum--;
    }
    return total;
}

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