n, h = map(int, input().split())
ab = [list(map(int, input().split())) for _ in range(n)]

a_all = [_ab[0] for _ab in ab]
b_all = [_ab[1] for _ab in ab]

a_max = max(a_all)

b_all_useful = []
for b in b_all:
    if b > a_max:
        b_all_useful.append(b)

b_all_useful.sort()

useful_sum = sum(b_all_useful)
if useful_sum > h:
    counter = 0
    i = 0
    while True:
        counter += b_all_useful[1 * i]
        i += 1
        if counter >= h:
            break
    print(i)

else:
    h_new = h - useful_sum
    import math
    print(math.ceil(h_new / a_max) + len(b_all_useful))
