#include <bits/stdc++.h>

using namespace std;

long sumOfGroup(int k) {
    int OddNumInSeq= 0;
    int SumOfAllOddIntegers =0;
    
    // Return the sum of the elements of the k'th group.
    for(int i = 1; i<=k; i++)
    {
        for (int j=1; j<=i; j++)
        {
           if (i == 1 && j ==1)
           {    
               OddNumInSeq = 1;
               SumOfAllOddIntegers = 1;
           }
           else
           {
               OddNumInSeq +=2;
               SumOfAllOddIntegers += OddNumInSeq;
           }    
        }
        
        if (i != k)
            SumOfAllOddIntegers = 0;
    }
      
    return SumOfAllOddIntegers;
}

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