Description: There is a string $$$a$$$ (unknown to you), consisting of lowercase Latin letters, encrypted according to the following rule into string $$$s$$$: - after each character of string $$$a$$$, an arbitrary (possibly zero) number of any lowercase Latin letters, different from the character itself, is added; - after each such addition, the character that we supplemented is added. You are given string $$$s$$$, and you need to output the initial string $$$a$$$. In other words, you need to decrypt string $$$s$$$. Note that each string encrypted in this way is decrypted uniquely. Input Format: The first line of the input contains a single integer $$$t$$$ ($$$1 \le t \le 1000$$$) — the number of test cases. The descriptions of the test cases follow. The first line of each test case contains a single integer $$$n$$$ ($$$2 \le n \le 100$$$) — the length of the encrypted message. The second line of each test case contains a string $$$s$$$ of length $$$n$$$ — the encrypted message obtained from some string $$$a$$$. Output Format: For each test case, output the decrypted message $$$a$$$ on a separate line. Note: In the first encrypted message, the letter $$$a$$$ is encrypted as $$$aba$$$, and the letter $$$c$$$ is encrypted as $$$cabac$$$. In the second encrypted message, only one letter $$$q$$$ is encrypted as $$$qzxcq$$$. In the third encrypted message, zero characters are added to each letter.