import math

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

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

max_a = max(a_list)
b_list.sort(reverse=True)

count = 0
for b in b_list:
    if b > max_a:
        count += 1
        H -= b
    else:
        break
    if H < 0:
        break

count += max(math.ceil(H / max_a), 0)
print(count)