n,x = gets.chomp.split(" ").map(&:to_i)
a = gets.chomp.split(" ").map(&:to_i)
c = Hash.new(0)
ans = 0
for i in 0..n-1
  c[a[i]] += 1
end
for i in 1..x-1
  if i == x-i
    ans += c[i]*(c[i]+1)/2
  else
    ans += c[i]*c[x-i]
  end
end
puts ans