This is coding problem please help me to solve this

Delete Element
Problem Statement
Antonio is a professor at the University of Berland and does research on nice arrays.A nice array is an array such that :
There is an element in the array = (Sum of all the elements of the array)/2.Like array = [1,3,6,2] is a nice array as the third element of the array = (1+3+6+2)/2 = 6, but array = [1,2,4] is not a nice array as there is no suchelement.
Given an array A of length N, you have to tell if it is possible to remove exactly one element from array A such that the resulting array is a nice array.
If it’s possible then print the position of that element. If there are many such elements, print the minimum position.
If there is no such element in array A, print "-1" instead.
Input Format
First line contains a single integer denoting N.
The next line contains N space-separated integers denoting the elements of array A.
Output Format
Print the position of the element such that removing it makes array A a nice array. If there is no such element in array A, print "-1" instead.
Constraints
2<=N<=105
1<=Ai<=109
Sample Input 1
5
5 2 1 2 2
Sample Output 1
2
Explanation of Sample 1
Removing the 2nd element will make array A = [5,1,2,2].
Here the first element of array A = (Sum of all the elements of the array)/2 = (5+1+2+2)/2 = 5.