N = gets.to_i.times.map{ gets.split.map(&:to_i) }
gets.to_i.times.map{gets.split.map(&:to_i)}
  .group_by{|x,y| N.count{|a,b| x >=a && y <= b } }
  .then do |h| 
    m = h.keys.max
    puts m == 0 ? 0 : h[m].size
  end