#include <bits/stdc++.h>

using namespace std;

void sumOfGroup(long long int k) {
    // Return the sum of the elements of the k'th group.
    vector<long long int> sum(1, 0);
        
    for (long long int i=k*(k-1) + 1, j=0; j<k; i+=2, j++) {
        //cout << i << endl;
        sum[0] += i;
        
        long long int carry = 0;
        int x;
        for (x = 0; x<sum.size(); x++) {
            long long int tmp = sum[x] + carry;
            sum[x] = tmp % 10000000;
            
            if (tmp >= 10000000) {
                carry = tmp / 10000000;
            } else
                carry = 0;
        }
        
        if (carry) {
            if (x == sum.size())
                sum.push_back(0);
            sum[x] += carry;
        }
            
    }
    
    cout << sum.back();
    
    for (int i=sum.size()-2; i>=0; i--) {
        printf("%07lld", sum[i]);
    }
    cout << endl;
}

int main() {
    int k;
    cin >> k;
    sumOfGroup(k);
    return 0;
}