import heapq as hq
from math import ceil
N, H = map(int, input().split())
A = 0
B = []
for i in range(N):
  a, b = map(int, input().split())
  A = max(A, a)
  hq.heappush(B, -b)

ans = 0
while H > 0 and B:
  b = -hq.heappop(B)
  if b > A:
    H -= b
    ans += 1
  else:
    break

if H > 0:
  ans += ceil(H / A)

print(ans)