n, x=gets.split.map(&:to_i)
a=gets.split.map(&:to_i)

cnt=Array.new(a.max+1){0}
a.each{|e| cnt[e]+=1}
ans=0
a.each do |e|
  next if x-e<0 or x-e>=cnt.size
  ans+=cnt[x-e]
end

puts ans