#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;
int a[101];
int ans;
int main()
{
	a[1]=1;
	for(int i=2;i<=100;i++)a[i]=a[i-1]+i;
	for(int i=1;i<=100;i++)ans+=a[i];
	cout<<ans<<endl;
	return 0;	
	
}