#include <fstream>

using namespace std;

ifstream fin("progresie.in");
ofstream fout("progresie.out");

int main()
{
	int t, n, r, n1, n2;
	fin >> t;
	while(t--)
	{
		fin >> n >> r;
		for(int i = 1; i * i < 1000000000; i++)
		{
			n2 = i * i;
			n1 = n2 - i + 1;
			if(n2 - n1 >= (n - 1) * r)
			{
				fout << n1 << "\n";
				break;
			}
		}
	}
	return 0;
}