package no3534_make_many_fence;
import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		StringBuilder sb = new StringBuilder();
		while(t > 0) {
			t--;
			long n = sc.nextInt();
			long m = sc.nextInt();
			long left = 0;
			long right = n;
			while(left < right - 1) {
				long mid = (left + right)/2;
				//フェンスを作る回数
				long make = (mid + 2)/3;
				//そのとき使う（加工を除いた)木材
				long w = make * 4;
				//そのとき使う棒の本数
				long b = make * 2;
				//のこりの木材
				long rw = n - w;
				//用意できる棒の本数
				long rb = m + (Math.max(0, rw)/2) * 4;
				if(rw >= 0 && rb >=b) {
					left = mid;
				}else {
					right = mid;
				}
			}System.out.println(left);
		}
		
	}

}