#! ruby
# yukicoder My Practice
# author: Leonardone @ NEETSDKASU

K = gets.to_i

count = 0

[2,3,5,7,11,13].each do |x|
	[4,6,8,9,10,12].each do |y|
		if x * y == K
			count += 1
		end
	end
end

puts (count.to_f / 36.0)