function parseInt(x) parse(Int, x) end
function main()
	n = parseInt.(split(readline()))
	x = Array{Int}(2, n[1])
	for i in 1:n[1]
		x[:,i] = map(parseInt, split(readline()))
	end
	maxa = maximum(x[1,:])
	useb = Int[]
	for i in 1:n[1]
		if x[2,i] > maxa
			push!(useb, x[2,i])
		end
	end
	hp = n[2]
	count = 0
	for i in 1:length(useb)
		if hp > 0
			hp -= useb[i]
			count += 1
		end
	end
	if hp > 0
		if hp%maxa == 0
			count += div(hp, maxa)
		else
			count += div(hp, maxa)+1
		end
	end
	print(count)
end

main()