n,h = map(int,input().split())
al,bl = [],[]
for i in range(n):
  a,b = map(int,input().split())
  al.append(a)
  bl.append(b)
ma = max(al)
bl.sort()
s = 0
c = 0
for i in bl[::-1]:
  if ma >= i:
    break
  else:
    s += i
    c += 1
    if s >= h:
      break
if h > s:
  c += (h-s-1)//ma+1
print(c)