gistfile1.py

#!/usr/bin/env python
import sys
import itertools
import collections

def Kdiff(nums, k):
    return sum(1 for x, y in itertools.combinations(nums, 2) if (x-y) == k)
def ErrorAndExit():
    print "0"
    sys.exit()
def main():
    n = k = 0
    try:
        n, k = raw_input().rstrip().split()
        n = int(n)
        k = int(k)
        if n > (10 ** 5) or n <= 0:#doesn't pass requirement on n
            ErrorAndExit()
        elif k >= (1 * (10**9)) or k <0:#doesn't pass requirement on k
            ErrorAndExit()
    except: #no k or just malformed input.  print 0 and exit
        ErrorAndExit()
    nums = collections.defaultdict(lambda: 1)
    def clg():
        for num in raw_input().rstrip().split():
            nums[ num ] += 1
        return nums
    
    print Kdiff( nums.iterkeys(), k )
    
if __name__ == '__main__':
    main()