N, H = map(int, input().split(' '))
katana = [map(int, input().split(' ')) for _ in range(N)]
dmg_wield, dmg_throw = zip(*katana)

dmg_wield_max = max(dmg_wield)
dmg_throw = [d for d in sorted(dmg_throw, reverse=True) if d >= dmg_wield_max]

n = len(dmg_throw)
H -= sum(dmg_throw)
n += int(H // dmg_wield_max)

if H - dmg_wield_max * n > 0:
    n += 1

print(n)