n = gets.to_i
cheby = gets.strip.split(' ').map(&:to_i)
#p @cheby
goal = gets.strip.split(' ').map(&:to_i).map(&:abs)
#p @goal

if goal == [0, 0]
	p "0"
	exit
end

goal_max = goal.max
cheby_max = cheby.max
if goal_max < cheby_max
	p (goal.max.to_f / cheby.max).ceil + 1
else
	p (goal.max.to_f / cheby.max).ceil
end