def f(a, b)
  _party = a.sort.map{|v| v * MOD}
  troop = b.map{|v| v / 2 * MOD}
  troop.size.times.inject(1.0/0){|r|
    party = _party.dup
    (troop.all?{|elv|
      lv_cnt = party.shift + elv + 1
      if lv_cnt % MOD < r
        nth = party.bsearch_index{|v| v >= lv_cnt} || party.size
        party.insert(nth, lv_cnt)
      end
    } ? [r, party.map{|v| v % MOD}.max].min : r).tap{
      troop.rotate!
    }
  }
end

N = gets.to_i
A = gets.split.take(N).map(&:to_i)
B = gets.split.take(N).map(&:to_i)
MOD = 2000
p f(A, B)