class Yukicoder
  def initialize
    t, c = gets.chomp.split.map(&:to_i)
    dp = Hash.new

    dp[1] = 1.0

    t.times do |i|
      temp = Hash.new

      dp.each do |k,v|
        [2,3,5,7,11,13].each do |n|
          if temp[k*v]
            temp[k*n] += v * 1/6r
          else
            temp[k*n] = v * 1/6r
          end
        end
      end

      dp = temp.dup
    end

    c.times do
      temp = Hash.new

      dp.each do |k,v|
        [4,6,8,9,10,12].each do |n|
          if temp[k*n]
            temp[k*n] += v * 1/6r
          else
            temp[k*n] = v * 1/6r
          end
        end
      end

      dp = temp.dup
    end

    ans = 0.0

    dp.each do |k,v|
      ans += k * v
    end

    puts ans
  end
end

Yukicoder.new