Array of unique integers and a target value k are given. Determine the number of pairs of array elements that have a difference equal to a target value k.
First line contains integers n (2≤n≤105) and k (0<k<109). Second line contains n unique integers in the range from 0 to 231−1.
Print the number of pairs of array integers with difference k.
In the sample there are two pairs of numbers with difference 3:(5,2) and (10,7).