n, h = map(int, input().split())
a = []
b = []
amax = 0
for i in range(n):
  ai, bi = map(int, input().split())
  if amax < ai:
    amax = ai
  a.append(ai)
  b.append(bi)

b = [b[j] for j in range(n) if b[j] > amax]
sumb = sum(b)
if sumb >= h:
  s = 0
  b = sorted(b)
  while s < h:
    s += b[-1]
    b.pop(-1)
  print(n-len(b))
else:
  print((h-sumb)//amax+((h-sumb)%amax!=0) + len(b))

