Given n non-negative integers, you need to find two integers a and b that a xor b is maximum. xor is exclusive-or.
Input starts with an integer T(T <= 10) denoting the number of tests.
For each test case, the first line contains an integer n(n <= 100000), the next line contains a1, a2, a3, ......, an(0 <= ai <= 1000000000);
For each test case, print you answer.