from math import ceil

N, H = map(int, input().split())
ABIn = [list(map(int, input().split())) + [i] for i in range(N)]

a_max, b_prime, index = sorted(ABIn, key=lambda x: x[0], reverse=True)[0]

ans = 0
for a, b, i in sorted(ABIn, key=lambda x: x[1], reverse=True):
    if b < a_max:
        break
    if i == index:
        if (H-b) <= 0:
            H -= b
            ans += 1
            break
        else:
            continue
    H -= b
    ans += 1
    if H <= 0:
        break

if H > 0:
    if b_prime > a_max:
        ans += 1 + ceil((H-b_prime)/a_max)
    else:
        ans += ceil(H / a_max)

print(ans)
