Smallest Concatenation

Concatenating two numbers $x$ and $y$ means writing the digits of $y$ right after the digits of $x$: concatenating $123$ and $45$ gives $12345$. Given an array of numbers, your task is to find the smallest number that can be obtained by concatenating all of them, each used exactly once, in some order.

Input

First line of input will be a single integer $t$ - the number of testcases.
Each testcase consists of two lines: the first contains an integer $n$ - the number of elements, and the second contains $n$ integers $a_0,a_1,\dots ,a_{n-1}$.

Output

For every testcase print a single line with the smallest number obtainable by concatenating all the given numbers.

Example

2
5
32 11 987 12 3
2
91919 919191

1112323987
91919191919

In the first testcase the order $11,12,32,3,987$ gives the smallest result - note that $32$ comes before $3$. In the second, starting with $919191$ beats starting with $91919$.

Constraints

$1\le t\le 1000$
$1\le n\le 10^5$
$1\le a_i\le 10^9$
$n_1+n_2+\dots +n_t\le 10^5$

This problem was adapted, with permission, from Najmanji broj nadovezivanjem više brojeva, authored by Društvo matematičara Srbije and Fondacija Petlja.