CF2037A Twice

Kinich wakes up to the start of a new day. He turns on his phone, checks his mailbox, and finds a mysterious present. He decides to unbox the present. Kinich unboxes an array $ a $ with $ n $ integers. Initially, Kinich's score is $ 0 $ . He will perform the following operation any number of times: - Select two indices $ i $ and $ j $ $ (1 \leq i < j \leq n) $ such that neither $ i $ nor $ j $ has been chosen in any previous operation and $ a_i = a_j $ . Then, add $ 1 $ to his score. Output the maximum score Kinich can achieve after performing the aforementioned operation any number of times.

The first line contains an integer $ t $ ( $ 1 \leq t \leq 500 $ ) — the number of test cases. The first line of each test case contains an integer $ n $ ( $ 1 \leq n \leq 20 $ ) — the length of $ a $ . The following line of each test case contains $ n $ space-separated integers $ a_1, a_2, \ldots, a_n $ ( $ 1 \leq a_i \leq n $ ).

For each test case, output the maximum score achievable on a new line.

In the first and third testcases, Kinich cannot perform any operations. In the second testcase, Kinich can perform one operation with $ i=1 $ and $ j=2 $ . In the fourth testcase, Kinich can perform one operation with $ i=1 $ and $ j=4 $ .