class Dic
  def initialize
    @word = [" "]
    @queue = []
  end
  
  def insert(str,i)
    @word << [str,i]
  end
  
  def find(str,i)
    @queue << [str,i]
  end
  
  def exe
    @word = @word.uniq{|item|item[0]}.sort_by{|item|item[0]}
    @queue.each do |str|
      if include?(@word, str)
        puts 'yes'
      else
        puts 'no'
      end
    end
  end
  
  def include?(arr, n)
    if arr.length == 1
      return ((arr[0][0] == n[0]) and (arr[0][1] < n[1]))
    else
      if arr[arr.length / 2][0] <= n[0]
        return include?(arr[arr.length / 2..arr.length - 1], n)
      else
        return include?(arr[0...arr.length / 2], n)
      end
    end
  end
end
def testf
  test = open("dic2.txt")
  dic = Dic.new
  i = 0
  test.gets
  while str = test.gets
    dic.send(*str.split(" "), i)
    i += 1
  end
  dic.exe
end
def f
  dic = Dic.new
  i = 0
  gets.to_i.times do
    dic.send(*gets.split(" "),i)
    i += 1
  end
  dic.exe
end
f