C++ :

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;

int main()
{
    int n,num=1;
    cin>>n;
    for(int i=n;i>=1;i--){
        num+=(3*i)+1;
    }
    cout<<num;
    return 0;
}

n = int(input())
ans = 0
for i in range(0,n+1):
    ans+=(3*i+1)

print(ans)

#include<bits/stdc++.h>
using namespace std;
int main()
{
	long long int n,sum=1;
	cin>>n;
	for(int i=1;i<=n;i++)
	sum+=(3*i)+1;
	cout<<sum;
}

n=int(input());print(int(n*(3*n+7)/2-n+1))