setting = input().rstrip().split(" ")
katana_count = int(setting[0])
HP = int(setting[1])

katana_attack = []
katana_throw = []

for i in range(katana_count):
    katana_status = input().rstrip().split(" ")
    katana_attack.append(int(katana_status[0]))
    katana_throw.append(int(katana_status[1])) 

throw = 0
attack = 0
throw_damege = 0
max_katana_attack = max(katana_attack)
for i in range(katana_count):
    if katana_throw[i] > max_katana_attack:
        throw +=1
        throw_damege += katana_throw[i]

HP = HP - throw_damege
if HP >0 :
    if HP % max_katana_attack != 0:
        attack = int(HP / max_katana_attack) +1
    else:
        attack = int(HP / max_katana_attack)

print(attack + throw)
