tmp = []
cnt = "0"
while cnt != [0, 0]
  i = gets.chomp.split.map(&:to_i)
  tmp.push(i)
  tmp.flatten!
  cnt = i
end
tmp.delete(tmp[-1])
num_of_element = tmp.length/2

i = 0
num_of_element.times do
  x = tmp[i]
  y = tmp[i+1]
  if x <= y
    puts "#{x} #{y}"
  else
    puts "#{y} #{x}"
  end
  i = i + 2
end