n,h = map(int, input().split())

ka = []
th = []

for _ in range(n):
    a, b = map(int, input().split())
    ka.append(a)
    th.append(b)

thr = sorted(th, reverse=True)

if max(ka) >= max(th):
    print(-(-h//max(ka)))
    exit()

res = 0
for i in range(n):
    if max(ka) < th[i]:
        h -= th[i]
        res += 1
        if h >1:
            pass
        else:
            print(res)
            exit()
    else:
        print(res+(-(-h//max(ka))))
        exit()