N,H = map(int,input().split())
A = [];B = []
for _ in range(N):
  a,b = map(int,input().split())
  A.append(a);B.append(b)
B.sort(reverse = True)
ma = max(A)
counter = 0
for b in B:
  if b > ma:
    counter += 1
    H -= b
    if H <= 0:
      print(counter)
      exit()
  else:
    break
counter += (H -1)//ma + 1
print(counter)