N, H = map(int, input().split())
a_list = []
b_list = []
for _ in range(N):
  a, b = map(int, input().split())
  a_list.append(a)
  b_list.append(b)
  
b_list = sorted(b_list)

count = 0
a_max = max(a_list)

while H > 0:
  b = b_list.pop()
  if b > a_max:
    H -= b
    count += 1
  else:
    break
    
if H > 0:
  if H % a_max == 0:
    count += H // a_max
  else:
    count += H // a_max + 1
    
print(count)

