import strutils, sequtils, tables

let
  tmp, a = map(split readLine stdin, parseInt)
  (N, X) = (tmp[0], tmp[1])
var
  b = initCountTable[int]()
  ans = 0

for i, ai in a:
  inc b, ai

for k, v in b:
  if X - k in b:
    ans += v * b[X - k]

echo ans