input

6

rabbits from 1 to 2 )

class Rabbit

  @@result = 1 


  def read
    File.open("./input", "r") do |file|  
      file.each_line do |line|
        trace(line.chomp, 2)
      end
    end    
  end

private 

  def trace(stairs, jump)
    max_jump = []
    stairs = stairs.to_i
    
    while stairs >= jump do
      stairs -= jump
      max_jump << jump
    end
    max_jump << 1 if stairs == 1 

    options(max_jump)
    puts @@result
  end

  def options(max_jump)
    max_jump.each_with_index do |jump, index|
      if jump == 2
        max_jump[index] = 1
        max_jump.insert(index + 1, jump - 1)
        @@result += 1
        options(max_jump)
      end  
    end  
  end
end


check = Rabbit.new
check.read