One and Two

Description:

Input:

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 100$$$). Description of the test cases follows.

The first line of each test case contains one integer $$$n$$$ ($$$2 \leq n \leq 1000$$$).

The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$1 \leq a_i \leq 2$$$).

Output:

For each test case, if there is no such $$$k$$$, print $$$-1$$$.

Otherwise, print the smallest possible $$$k$$$.

Sample Input:

3
6
2 2 1 2 1 2
3
1 2 1
4
1 1 1 1

Sample Output:

2
-1
1

Note:

For the first test case, $$$k=2$$$ satisfies the condition since $$$a_1 \cdot a_2 = a_3 \cdot a_4 \cdot a_5 \cdot a_6 = 4$$$. $$$k=3$$$ also satisfies the given condition, but the smallest should be printed.

For the second test case, there is no $$$k$$$ that satisfies $$$a_1 \cdot a_2 \cdot \ldots \cdot a_k = a_{k+1} \cdot a_{k+2} \cdot \ldots \cdot a_n$$$

For the third test case, $$$k=1$$$, $$$2$$$, and $$$3$$$ satisfy the given condition, so the answer is $$$1$$$.