Python

import sys 
from collections import defaultdict 
 
def main():
    n, c = map(int, sys.stdin.readline().split()) 
    freq = defaultdict(int)
    for _ in range(n):
        a = int(sys.stdin.readline()) 
        freq[a] += 1 
    ans = 0 
    for a in freq:
        ans += freq[a] * freq.get(a  + c, 0)
    print(ans)
 
if __name__ == "__main__":
    main()