local n,h=io.read("*n","*n")
local a={}
local b={}
for i=1,n do
    a[i],b[i]=io.read("*n","*n")
end
table.sort(a)
table.sort(b)

local attack=0
for i=n,1,-1 do
    if b[i]>=a[n] then
        h=h-b[i]
        attack=attack+1
    end
    if 0>=h then
        print(attack)
        return
    end
end
print(attack+math.ceil(h/a[n]))