N=80-gets.to_i
P=gets.split.map &:to_i
f=(0..14).to_a
N.times{
  14.downto(0){|m|
    q=(0..m+1).map{|k|
      k<1||k>m ?1:P[m<2?0:k<2||k>m-1?1:2]/1e2
    }
    s=0
    1.upto(m){|i|i.upto(m){|j|
      t=f[j-i+1]*q[i-1]*q[j+1]
      i.upto(j){|k|
        t*=1-q[k]
      }
      s+=t
    }}
    f[m]=s
  }
}
p f[14]*2