#include <bits/stdc++.h>

using namespace std;

long sumOfGroup(int k) {
   int item=(k+k+1);
    long sum=0;
    int found=0;
    do
      {
        if(item % 2 !=0)
        {
          sum+=item;
          found++;
        }
         item++;
      }while(found != k);

    return sum;
}

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