A. Subset Mextime limit per test1 secondmemory limit per test512 megabytesinputstandard inputoutputstandard outputGiven a set of integers (it can contain equal elements).You have to split it into two subsets A and B (both of them can contain equal elements or be empty). You have to maximize the value of mex(A)+mex(B).Here mex of a set denotes the smallest non-negative integer that doesn't exist in the set. For example:   mex(\{1,4,0,2,2,1\})=3  mex(\{3,3,2,1,3,0,0\})=4  mex(\varnothing)=0 (mex for empty set) The set is splitted into two subsets A and B if for any integer number x the number of occurrences of x into this set is equal to the sum of the number of occurrences of x into A and the number of occurrences of x into B.InputThe input consists of multiple test cases. The first line contains an integer t (1\leq t\leq 100) — the number of test cases. The description of the test cases follows.The first line of each test case contains an integer n (1\leq n\leq 100) — the size of the set.The second line of each testcase contains n integers a_1,a_2,\dots a_n (0\leq a_i\leq 100) — the numbers in the set.OutputFor each test case, print the maximum value of mex(A)+mex(B).ExampleInput
4
6
0 2 1 5 0 1
3
0 1 2
4
0 2 0 1
6
1 2 3 4 5 6
Output
5
3
4
0
NoteIn the first test case, A=\left\{0,1,2\right\},B=\left\{0,1,5\right\} is a possible choice.In the second test case, A=\left\{0,1,2\right\},B=\varnothing is a possible choice.In the third test case, A=\left\{0,1,2\right\},B=\left\{0\right\} is a possible choice.In the fourth test case, A=\left\{1,3,5\right\},B=\left\{2,4,6\right\} is a possible choice.
4
6
0 2 1 5 0 1
3
0 1 2
4
0 2 0 1
6
1 2 3 4 5 6

5 3 4 0 
['greedy', 'implementation', 'math', '*900']