In statistics, the mode of a set of values is the value that occurs most often or with the greatest frequency.

Write a function that accepts as arguments the following:

A. An array of integers

B. An integer that indicates the number of elements in the array

The function should determine the mode of the array.

That is, it should determine which value in the array occurs most often. The mode is the value the function should return.

If the array has no mode (none of the values occur more than once), the function should return -1. (Assume the always array will contain nonnegative values.)