#include<iostream>
#include <math.h>
using namespace std;


int main()
{
	int d;
	while(cin>>d)
	{
		int sumsum=1;
		int sum=1;
		int adder=1;
		for(int num=2;num<=50;num++)
		{
			sum = sum+adder;
			adder=adder+d;
			//cout<<sum<<"  ";
			sumsum+=sum;
		}
		//cout<<endl;
		cout<<sumsum<<endl;
	}
}