Pairs with Difference K

Medium#arrays #hashing· solved by 0 · time limit 2.0 s

Count the distinct value pairs $(x, y)$ in the array with $y - x = k$ . (For $k = 0$ , count values that appear at least twice.)

Input

$n$ , then $n$ integers, then $k$ .

The number of distinct pairs.

$1 \le n \le 10^5$ , $0 \le k \le 10^9$

Input

5
3 1 4 1 5
2

Output

Input

5
1 3 1 5 4
0

Output