Given a list of N positive integers X, each integer except one has even copies, please output the integer which does not have even copies in the list. (N is odd number and guarantee only one integer has odd copies)
( 1 <= N <= 1,000,000  and  1 <= X_i <= 2¹⁵ )

There are M test cases, ( 0 < M < 100 )
For each case, the first line is integer N and the second line has N integers.
when the case with N = 0, all the input was done

For each case, output one integer which is the number having odd number of copies in the case