#include <bits/stdc++.h>
using namespace std;

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

int GetGroup(int64_t x) {
	return (int)sqrt(x - 1.0) + 1;
}

pair<int64_t, int64_t> GetGroupLimits(int g) {
	return make_pair(1LL * g * (g - 1) + 1, 1LL * g * g);
}

int main() {
	int testCount;
	fin >> testCount;

	while (testCount--) {
		int N, R;
		fin >> N >> R;

		for (int startGroup = 1;; ++startGroup) {
			int64_t curr = GetGroupLimits(startGroup).first;
			int64_t freeMove = startGroup - 1;

			bool found = true;
			for (int step = 2; step <= N; ++step) {
				curr += R;
				int currGroup = GetGroup(curr);

				int64_t start, finish;
				tie(start, finish) = GetGroupLimits(currGroup);

				if (curr < start) {
					if (start - curr <= freeMove) {
						freeMove -= start - curr;
						curr = start;
					}
					else {
						found = false;
						break;
					}
				}

				freeMove = min(freeMove, finish - curr);
			}

			if (found) {
				fout << curr - 1LL * (N - 1) * R << '\n';
				break;
			}
		}
	}

	return 0;
}

//Trust me, I'm the Doctor!