from sys import stdin
input = stdin.readline
import collections
def solve():
    N, D = map(int, input().split())
    A = list(map(int, input().split()))
    
    right_cnt = collections.Counter(A)
    left_cnt= collections.Counter()
    ans = 0
    
    for x in A:
        right_cnt[x] -= 1
        val_i = x - D
        val_k = x + D

        count_i = left_cnt[val_i]
        count_k = right_cnt[val_k]
        
        if count_i > 0 and count_k > 0:
            ans += count_i * count_k
            
        left_cnt[x] += 1
    print(ans)

if __name__ == "__main__":
    solve()