n=gets.to_i
a=gets.split.map(&:to_i).sort+[1e9]
b=gets.split.map(&:to_i)
p (1..n).map{|i|
  pq=a.map{|j|[j,0]}
  b.rotate(i).each{|e|
    l,c=pq.shift
    up=[l+e/2,c+1]
    pq[(0..n-1).bsearch{|x|(pq[x]<=>up)>=0},0]=[up]
  }
  pq[0..-2].map{|x,y|y}.max
}.min