N, H = map(int, input().split())
A, B = [0 for _ in range(N)], [0 for _ in range(N)]
for i in range(N):
  A[i], B[i] = map(int, input().split())
m = max(A)
B.sort(reverse=True)
cnt = N - 1
while B[cnt] < m:
  cnt -= 1
ccnt = 0
for i in range(cnt+1):
  H -= B[i]
  ccnt += 1
  if H <= 0:
    break
if H > 0:
  ccnt += -(-H//m)
print(ccnt)