N, HP = map(int, input().split())

hit = []
throw = []
for i in range(N):
    h, t = map(int, input().split())
    hit.append(h)
    throw.append(t)

h = max(hit)
throw.sort()
throw.reverse()

ans = 0
for t in throw:
    if t < h:
        break
    else:
        ans += 1
        HP -= t
        print("throw", HP, h)
        if HP <= 0:
            break

while HP > 0:
    ans += 1
    HP -= h
print(ans)