gets
la=gets.split.map(&:to_i)
k=gets.to_i

eps=1e-9
l=0.0
r=1e9

while [(l-r).abs,(l-r).abs/r].all?{|d|d>eps}
  c=(l+r)/2
  la.map{|i|(i/c).to_i}.inject(:+)>=k ?(l=c):(r=c)
end

p (l+r)/2