T = int(input())
for _ in range(T):
    N,M = map(int,input().split())
    k = max(0,(N-2*M)/10)
    k1 = int(k)
    k2 = int(k+1)
    f1 = min((N-2*k1)//4,(M+4*k1)//2)
    f2 = min((N-2*k2)//4,(M+4*k2)//2)
    ans = print(3*max(f1,f2))