import sys
input = sys.stdin.readline

T=int(input())

for tests in range(T):
    L,R=list(map(int,input().split()))

    y=-1

    for i in range(40):
        x=2**i

        if L<=x<=R:
            y=x

    if y==-1:
        print(-1)
    else:
        if L<=y-1<=R:
            ANS=y*(y-1)
        else:
            ANS=-1

        print(ANS)