Problem A: XOR
Given two integers S and F, what is the
XOR (exclusive-or) of
all numbers between S and F (inclusive)?
Input Specification
The first line of input is the integer T, which is the number of
test cases (1 ≤ T ≤ 1000).
T lines follow, with each line containing two integers S
and F
(1 ≤ S ≤ F ≤ 1 000 000 000).
Output Specification
For each test case, output the (decimal) value of the XOR of all numbers
between S and F, inclusive.
Sample Input
5
3 10
5 5
13 42
666 1337
1234567 89101112
Output for Sample Input
8
5
39
0
89998783