n = gets.to_i

def prime?(n)
  if n == 1
    return false
  end
  2.upto(Math.sqrt(n)) do |i|
    return false if n % i == 0
  end
  true
end

(1..n).each do |k|
  if prime?(k)
    print "#{k} "
  end
end

# 入力 10
#=> 2 3 5 7

require 'prime'
n = gets.to_i

(1..n).each do |k|
  if Prime.prime?(k)
    print "#{k} "
  end
end

# 入力 10
#=> 2 3 5 7