405361: GYM101915 F A Missing Problem in TCPC2017

While the judges of TCPC were busy preparing the problems, they encountered a strange problem. One of the problems was missing !!

The judges remember that they prepared exactly N problems and that they were numbered from 1 to N. They also remembered that the problems were sorted according to their number.

The judges started investigating but they realized that they don't have enough time, so they asked the contestants for help.

The first line contains a single integer T, the number of test cases.

The first line of each test case consists of a single integer N (2 ≤ N ≤ 12), denoting the number of problems.

The second line of each test case contains N - 1 space separated integer denoting the number of each problem the judges didn't miss. Yet!

it's guaranteed that the numbers are given in the increasing order.

For each test case print a single line, containing a single integer, denoting the number of the missing problem.

1
4
1 2 4

3