from math import ceil
N, H = map(int, input().split())
B = []
maxa = 0
cnt = 0

for i in range(N):
  a,b = map(int, input().split())
  maxa = max(maxa,a)
  B.append(b)

B.sort(reverse=True)

for i in range(N):
  if B[i] < maxa:
    break
  cnt += 1
  H -= B[i]
  if H <= 0:
    print(cnt)
    exit(0)

cnt += ceil(H / maxa)

print(cnt)