A binary string is a string where each character is either 0 or 1. Two binary strings $$$a$$$ and $$$b$$$ of equal length are similar, if they have the same character in some position (there exists an integer $$$i$$$ such that $$$a_i = b_i$$$). For example:
You are given an integer $$$n$$$ and a binary string $$$s$$$ consisting of $$$2n-1$$$ characters. Let's denote $$$s[l..r]$$$ as the contiguous substring of $$$s$$$ starting with $$$l$$$-th character and ending with $$$r$$$-th character (in other words, $$$s[l..r] = s_l s_{l + 1} s_{l + 2} \dots s_r$$$).
You have to construct a binary string $$$w$$$ of length $$$n$$$ which is similar to all of the following strings: $$$s[1..n]$$$, $$$s[2..n+1]$$$, $$$s[3..n+2]$$$, ..., $$$s[n..2n-1]$$$.
The first line contains a single integer $$$t$$$ ($$$1 \le t \le 1000$$$) — the number of test cases.
The first line of each test case contains a single integer $$$n$$$ ($$$1 \le n \le 50$$$).
The second line of each test case contains the binary string $$$s$$$ of length $$$2n - 1$$$. Each character $$$s_i$$$ is either 0 or 1.
For each test case, print the corresponding binary string $$$w$$$ of length $$$n$$$. If there are multiple such strings — print any of them. It can be shown that at least one string $$$w$$$ meeting the constraints always exists.
4 1 1 3 00000 4 1110000 2 101
1 000 1010 00
The explanation of the sample case (equal characters in equal positions are bold):
The first test case:
The second test case:
The third test case:
The fourth test case:
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