Given an unsorted array Arr and a number N. You need to write a program to find if there exists a pair of elements in the array whose difference is N.
First line of input contains an integer T which denotes the number of test cases. Then T test cases follows. First line of each test case contains two space separated integers L and N where L denotes the length of array or the number of elements in the array and N denotes the difference between two elements. Second line of each test case contains L space separated integers which denotes the elements of the array.
For each test case, in a new line print 1 if the pair is found otherwise print -1 if there does not exist any such pair.