n, x = gets.split.map(&:to_i)
a = gets.split.map(&:to_i)
table = a.group_by(&:itself).map { |k,v| [k,v.size] }.to_h
count = 0
table.each_key do |k|
    count += table[k] * (table[x - k] || 0)
end
puts count