CF1698A.XOR Mixup

传统题 时间 2000 ms 内存 256 MiB 3 尝试 1 已通过 1 标签

XOR Mixup

There is an array aa with n1n-1 integers. Let xx be the bitwise XOR of all elements of the array. The number xx is added to the end of the array aa (now it has length nn), and then the elements are shuffled.

You are given the newly formed array aa. What is xx? If there are multiple possible values of xx, you can output any of them.

Input

The input consists of multiple test cases. The first line contains an integer tt (1t10001 \leq t \leq 1000) — the number of test cases. The description of the test cases follows.

The first line of each test case contains an integer nn (2n1002 \leq n \leq 100) — the number of integers in the resulting array aa.

The second line of each test case contains nn integers a1,a2,,ana_1, a_2, \ldots, a_n (0ai1270 \le a_i \le 127) — the elements of the newly formed array aa.

Additional constraint on the input: the array aa is made by the process described in the statement; that is, some value of xx exists.

Output

For each test case, output a single integer — the value of xx, as described in the statement. If there are multiple possible values of xx, output any of them.

Note

In the first test case, one possible array aa is a=[2,5,4]a=[2, 5, 4]. Then x=254=3x = 2 \oplus 5 \oplus 4 = 3 (\oplus denotes the bitwise XOR), so the new array is [2,5,4,3][2, 5, 4, 3]. Afterwards, the array is shuffled to form [4,3,2,5][4, 3, 2, 5].

In the second test case, one possible array aa is a=[1,10,6,10]a=[1, 10, 6, 10]. Then x=110610=7x = 1 \oplus 10 \oplus 6 \oplus 10 = 7, so the new array is [1,10,6,10,7][1, 10, 6, 10, 7]. Afterwards, the array is shuffled to form [6,1,10,7,10][6, 1, 10, 7, 10].

In the third test case, all elements of the array are equal to 66, so x=6x=6.

In the fourth test case, one possible array aa is a=[100,100]a=[100, 100]. Then x=100100=0x = 100 \oplus 100 = 0, so the new array is [100,100,0][100, 100, 0]. Afterwards, the array is shuffled to form [100,100,0][100, 100, 0]. (Note that after the shuffle, the array can remain the same.)

Samples

4
4
4 3 2 5
5
6 1 10 7 10
6
6 6 6 6 6 6
3
100 100 0
3
7
6
0

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