String Similarity

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:

• 10010 and 01111 are similar (they have the same character in position 4);
• 10010 and 11111 are similar;
• 111 and 111 are similar;
• 0110 and 1001 are not similar.

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} ... 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].

Input

The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases.

The first line of each test case contains a single integer n (1 ≤ n ≤ 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.

Output

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.

Example

Input

4 1 1 3 00000 4 1110000 2 101

Output

1 000 1010 00

Note

The explanation of the sample case (equal characters in equal positions are bold):

The first test case:

• 1 is similar to s[1..1] = 1.

The second test case:

• 000 is similar to s[1..3] = 000;
• 000 is similar to s[2..4] = 000;
• 000 is similar to s[3..5] = 000.

The third test case:

• 1010 is similar to s[1..4] = 1110;
• 1010 is similar to s[2..5] = 1100;
• 1010 is similar to s[3..6] = 1000;
• 1010 is similar to s[4..7] = 0000.

The fourth test case:

• 00 is similar to s[1..2] = 10;
• 00 is similar to s[2..3] = 01.

inputFormat

Input

The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases.

The first line of each test case contains a single integer n (1 ≤ n ≤ 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.

outputFormat

Output

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.

Example

Input

4 1 1 3 00000 4 1110000 2 101

Output

1 000 1010 00

Note

The explanation of the sample case (equal characters in equal positions are bold):

The first test case:

• 1 is similar to s[1..1] = 1.

The second test case:

• 000 is similar to s[1..3] = 000;
• 000 is similar to s[2..4] = 000;
• 000 is similar to s[3..5] = 000.

The third test case:

• 1010 is similar to s[1..4] = 1110;
• 1010 is similar to s[2..5] = 1100;
• 1010 is similar to s[3..6] = 1000;
• 1010 is similar to s[4..7] = 0000.

The fourth test case:

• 00 is similar to s[1..2] = 10;
• 00 is similar to s[2..3] = 01.

样例

4
1
1
3
00000
4
1110000
2
101

1
000
1100
11

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