#include <bits/stdc++.h>

using namespace std;



int main() {
    
    long long int k;
    cin >> k;
    
    long long int num=0;
    
    for(long long int i=1;i<k;i++)
    {
        num = num + i;
    }
    
    long long int count=1,n=1;
    
    while(count<=num)
    {
        n=n+2;
        count++;
    }
    
    num = num + k;
    long long int sum=0;
    n=n-2;
   // count=count-1;
    while(count<=num)
    {
        n=n+2;
        //cout<<n<<" ";
        sum=sum+n;
        count++;
    }
    
    cout<<sum;
    
    return 0;
}