N=io.read()
H=io.read()
local number
local a={}
local b={}
for i=1,N do
  a[i]=io.read()
  b[i]=io.read()
end
local amax=0
for i=1,N do
  if a[i]>amax then
    amax=a[i]
  end
end
for i=1,N do
  if b[i]<amax then
    table.remove(a,i)
    table.remove(b,i)
  end
end
local c={}
for i,v in ipairs(b) do
  c[i]=v
end
table.sort(c,function (a,b) return a>b end)
local s=0
for i=1,#c do
  s=s+c[i]
end
local t=0
if s>=H then
  for i=1,#c do
    t=t+c[i]
    if t>=H then
      number=i
    end
    break
  end
else
  number=((H-s)//amax)+1+#c
end
print(number)