B'There is an array a with n-1 integers. Let x be the bitwise XOR of all elements of the array. The number x is added to the end of the array a (now it has length n ), and then the elements are shuffled. You are given the newly formed array a . What is x ? If there are multiple possible values of x , you can output any of them. The input consists of multiple test cases. The first line contains an integer t ( 1 <= q t <= q 1000 ) -- the number of test cases. The description of the test cases follows. The first line of each test case contains an integer n ( 2 <= q n <= q 100 ) -- the number of integers in the resulting array a . The second line of each test case contains n integers a_1, a_2, ldots, a_n ( 0 <= a_i <= 127 ) -- the elements of the newly formed array a . Additional constraint on the input: the array a is made by the process described in the statement; that is, some value of x exists. For each test case, output a single integer -- the value of x , as described in the statement. If there are multiple possible values of x , output any of them. In the first test case, one possible array a is a=[2, 5, 4] . Then x = 2 oplus 5 oplus 4 = 3 ( oplus denotes the bitwise XOR), so the new array is [2, 5, 4, 3] . Afterwards, the array is shuffled to form [4, 3, 2, 5] . In the second test case, one possible array a is a=[1, 10, 6, 10] . Then x = 1 oplus 10 oplus 6 oplus 10 = 7 , so the new array is [1, 10, 6, 10, 7] . Afterwards, the array is shuffled to form [6, 1, 10, 7, 10] . In the third test case, all elements of the array are equal to 6 , so x=6 . In the fourth test case, one possible array a is a=[100, 100] . Then x = 100 oplus 100 = 0 , so the new array is [100, 100, 0] . Afterwards, the array is shuffled to form [100, 100, 0] .'...