#include <bits/stdc++.h>
using namespace std;
int main(){
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	int t;
	cin >> t;
	while (t--)[&]{
		int N, M;
		cin >> N >> M;
		long long l = 0, r = 1e12;
		while (r - l > 1){
			long long mid = (l + r) / 2;
			if (mid * 4 + max(0LL, mid * 2 - M + 3) / 4 * 2 <= N){
				l = mid;
			} else {
				r = mid;
			}
		}
		cout << l * 3 << endl;
	}();
}