n,h = (int(i) for i in input().split())
a = []
b = []
cnt = 0
for i in range(n):
  x,y = (int(i) for i in input().split())
  a.append(x)
  b.append(y)
max = max(a)
b.sort()
for i in b[::-1]:
  if i > max:
    h -= i
    cnt += 1

  if h <= 0:

    exit()
import math
cnt += int(math.ceil(h / max))
print(cnt)