import bisect
import math
N, H = map(int, input().split())
A = []
B = []
for i in range(N):
  a, b = map(int, input().split())
  A.append(a)
  B.append(b)
am = max(A)
B.sort()
idx = bisect.bisect_right(B, am)
ans = 0
for i in range(1, N-idx+1):
  H -= B[-i]
  ans += 1
  if H <= 0:
    print(ans)
    exit()
print(ans + math.ceil(H/am))