def main():
    l, r = list(map(int, input().split()))
    ans = -1
    if l == 0:
        ans = 0
    if len(bin(l)) == len(bin(r)):
        return ans
    le = len(bin(r))-3
    return pow(2, le) * (pow(2, le)-1)

for _ in range(int(input())):
    print(main())