# 全部出す版
N,H=gets.chomp.split(' ').map{|n| n.to_i}
a = Array.new(N) { |i| 0 }
b = Array.new(N) { |i| 0 }
0.upto(N-1){|i|
	a[i], b[i] = gets.chomp.split(' ').map{|n| n.to_i}
}
amax = a.sort{|a,b| b <=> a}[0]
dmg = 0
atknum = 0
b.select{|bi| bi > amax}.each{|bi|
	dmg += bi
	atknum += 1
	if(dmg >= H)
		puts "#{atknum}"
		break
	end
}
if(dmg < H)
	#amax = a.sort[0]
	remdmg = H - dmg
	atknum += remdmg / amax
	if(remdmg % amax != 0)
		atknum += 1
	end
	puts "#{atknum}"
end


