N, H = map(int, input().split())
A, B = [], []

for _ in range(N):
    ai, bi = map(int, input().split())
    A.append(ai)
    B.append(bi)


# 最後に振り続ける刀 amax より大きい投げパワーの刀を全部投げる
amax = max(A)
iamax = A.index(amax)
count = 0
for k in range(N):
    if k != iamax and B[k] >= B[iamax]:
        count += 1
        H -= B[k]
        if H <= 0:
            print(count)
            exit()

# 残ったHPを倒し切る分 amax を降る
# count += ((H + amax - 1) / amax)
count += H // amax
print(count)