Given two integers, L and R, find the maximal value of A xor B,
where A and B satisfy the following condition:

L ≤ A ≤ B ≤ R

Input Format:

First line contains T,number of test cases
following T lines containing 2 intergers L and R ; L is present in the first line and R in
the second line.

Output Format:

T lines containing the maximal value as mentioned in the problem statement.

Constraints: 

1≤L≤R≤103

SAMPLE INPUT
1
10 15

SAMPLE OUTPUT
7

Explanation

The input tells us that L=10 and R=15. All the pairs which comply
to above condition are the following: 

10⊕10=0
10⊕11=1
10⊕12=6
10⊕13=7
10⊕14=4
10⊕15=5
11⊕11=0
11⊕12=7
11⊕13=6
11⊕14=5
11⊕15=4
12⊕12=0
12⊕13=1
12⊕14=2
12⊕15=3
13⊕13=0
13⊕14=3
13⊕15=2
14⊕14=0 
14⊕15=1 
15⊕15=0 

Here two pairs (10, 13) and (11, 12) have maximum xor value 7, and
this is the answer.

见题面

见题面