#include<stdio.h>
void solve()
{
	long long int N, M;
	scanf("%lld %lld", &N, &M);
	long long int min, mid, max;
	min = -1;
	max = 1e9;
	long long int n, m, d;
	while (max - min > 1)
	{
		mid = (max + min) / 2;
		n = N;
		m = M;
		if (m / 2 < mid)
		{
			d = 2 * mid - m;
			while (d % 4 > 0)
				d++;
			m += d;
			n -= d / 2;
		}
		if (n < 0)
			max = mid;
		else if (n / 4 < mid)
			max = mid;
		else
			min = mid;
	}
	printf("%lld\n", 3 * min);
	return;
}
int main()
{
	int t;
	scanf("%d", &t);
	for (; t > 0; t--)
		solve();
	return 0;
}