A15614. Add Plus Minus Sign

AquaMoon has a string $a$ consisting of only $0$ and $1$ . She wants to add $+$ and $-$ between all pairs of consecutive positions to make the absolute value of the resulting expression as small as possible. Can you help her?

The first line contains a single integer $t$ ( $1 \leq t \leq 2\,000$ ) – the number of test cases. The description of test cases follows.

The first line of each test case contains a single integer $n$ ( $2 \leq n \leq 100$ ) — the length of $a$ .

The second line of each test case contains a string $a$ of length $n$ , consisting of only $0$ and $1$ .

For each test case, output a string of length $n - 1$ consisting of $-$ and $+$ on a separate line. If there is more than one assignment of signs that produces the smallest possible absolute value, any of them is accepted.

In the first test case, we can get the expression $1 - 1 = 0$ , with absolute value $0$ .

In the second test case, we can get the expression $0 + 1 - 1 + 0 + 1 = 1$ , with absolute value $1$ .

In the third test case, we can get the expression $1 + 0 + 0 + 0 - 1 = 0$ , with absolute value $0$ .