Element Merger

Have the function ElementMerger(arr) take the array of positive integers stored in arr and perform the following algorithm: continuously get the difference of adjacent integers to create a new array of integers, then do the same for the new array until a single number is left and return that number. For example: if arr is [4, 5, 1, 2, 7] then taking the difference of each pair of elements produces the following new array: [1, 4, 1, 5]. Then do the same for this new array to produce [3, 3, 4] -> [0, 1] -> 1. So for this example your program should return the number 1 because that is what's left at the end.

Examples

Input: [5, 7, 16, 1, 2]
Output: 7

Input: [1, 1, 1, 2]
Output: 1