function main()
	lines=readlines()
	N,H=map(x->parse(Int,x),split(shift!(lines)))
	A=Array{Int}(0)
	B=Array{Int}(0)
	for s=lines
		a,b=map(x->parse(Int,x),split(s))
		push!(A,a)
		push!(B,b)
	end
	a=maximum(A)
	ans=0
	sort!(B)
	reverse!(B)
	for b=B
		if b<a||H<0
			break
		end
		H-=b
		ans+=1
	end
	println(ans+cld(H,a))
end
main()
