using namespace std;
int main(){
	int count, num,val[4010], tmp[4010];
	val[0] = 4;
	tmp[0] = 6;
	for (int a = 0; a < 4010; a++){
		tmp[a + 1] = tmp[a] + a + 4;
	}
	for (int a = 0; a < 4010; a++){
		val[a + 1] = val[a] + tmp[a];
	}
	while (cin >> num){
		cout << val[num - 1]<<endl;
	}
}