Given an array A of N positive numbers. The task is to find the position where equilibrium first occurs in the array. Equilibrium position in an array is a position such that the sum of elements before it is equal to the sum of elements after it.

Input:
The first line of input contains an integer T, denoting the number of test cases. Then T test cases follow. First line of each test case contains an integer N denoting the size of the array. Then in the next line are N space separated values of the array A.

Output:
For each test case in a new line print the position at which the elements are at equilibrium if no equilibrium point exists print -1.

Constraints:
1 <= T <= 100
1 <= N <= 10^{6} 1 <= A_{i} <= 10^{8}

Example:
Input:
2
1
1
5
1 3 5 2 2

Output:
1
3

Explanation: Testcase 1: Since its the only element hence its the only equilibrium point. Testcase 2: For second test case equilibrium point is at position 3 as elements below it (1+3) = elements after it (2+2).