N, H = map(int, input().split())
AB = [list(map(int, input().split())) for _ in range(N)]
A = [i[0] for i in AB].sort()
B = [i[1] for i in AB].sort()

count= 0
while len(B) > 0:
    damage = B.pop()
    H -= damage
    count += 1
    if H <= 0:
        print(count)
        return

count += round(H/A[-1])
print(count)
