a = []
h, w = gets.split(' ')
while line = gets
	a << line.split(' ')
end
a = a.flatten.map{|aij| aij.to_i}.sort
(0...h.to_i).each do |j|
	(0...w.to_i).each do |i|
		printf("#{a[i + j * w.to_i]} ")
	end
	printf "\n"
end