n = gets.to_i
d = gets.split.map(&:to_i)
x, y = gets.split.map(&:to_i)
c = [x.abs, y.abs].max
ans = if c == 0
        0
      elsif d.any? {|z| z == c}
        1
      elsif c < d.max
        2
      else
        c.fdiv(d.max).ceil
      end
puts ans