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 dmg_throw if d > dmg_wield_max]

n = 0
while H > 0 and dmg_throw:
    H -= dmg_throw.pop()
    n += 1

print(n + max(H-1, -1) // dmg_wield_max + 1)