#!/usr/bin/env ruby

require 'zipf'

dense_features = ReadFile.readlines_strip "#{File.dirname(__FILE__)}/dense_features.txt"

sep = " "

while line = STDIN.gets
  a = line.strip.split
  a.reject! { |i|
    !dense_features.include?(i.split('=').first)
  }
  puts a.join sep
end