require'timeout'
n,pa,pb=gets.split.map(&:to_f)
n=n.to_i
a,b=$<.map{|l|l.split.map(&:to_i).sort}

sum=0.0
cnt=0
begin
  timeout(2.9){
    loop{
      al=a.dup
      bl=b.dup
      ap=bp=0
      n.times{
        at=al.delete_at(al[1]&&rand>pa ?([*1..al.size-1].sample):0)
        bt=bl.delete_at(bl[1]&&rand>pb ?([*1..bl.size-1].sample):0)
        if at>bt
          ap+=at+bt
        else
          bp+=at+bt
        end
      }
      sum+=1 if ap>bp
      cnt+=1
    }
  }
rescue Timeout::Error
end
p sum/cnt