n, h = map(int, input().split())
l = []
for i in range(n):
  l.append(list(map(int,input().split())))

l = sorted(l, key=lambda x: x[1])
l = sorted(l, reverse=True, key=lambda x: x[0])
c = 0
for i in range(1, n):
  if l[i][1] > l[0][0]:
    h -= l[i][1]
    c += 1
    if h <= 0:
      print(c)
      exit()

while h > l[0][1]:
  h -= l[0][0]
  c += 1

print(c+1)
