class Yukicoder
  def initialize
    n, m = gets.chomp.split.map(&:to_i)
    fibo = Array.new(n+1, 0)
    fibo[1] = 1
    fibo[2] = 1

    3.upto(3+n) do |i|
      fibo[i] = fibo[i-1] + fibo[i-2]
    end

    diff = fibo[n] - m

    if diff < 0
      puts -1
    else
      answer = 0
      index = n-2

      while diff > 0 && index > 0
        if fibo[index] <= diff
          answer += 1
          diff -= fibo[index]
        end

        index -= 1
      end

      if diff == 0 
        puts answer
      else
        puts -1
      end
    end
  end
end

Yukicoder.new