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)

max_a = max(a_list)
b_list = [ i for i in b_list if i > max_a ]
b_list.sort(reverse = True)

total = 0
count = 0
for b in b_list:
    total += b
    count += 1
    if total > H:
        break

if total < H:
   count += int(-(-(H - total)) // max_a)

print(count)