N, HP = map(int, input().split())

K = []
A = []
B = []
for _ in range(N):
  a, b = map(int, input().split())
  B.append(b)
  A.append(a)
  
MA = max(A)
ans = 0
for b in sorted(B, reverse=True):
  HP -= b
  ans += 1
  if HP <= 0:
    exit()
    
  if MA > b:
    break

ans += HP // MA
print(ans)