import math

Num,HP = (map(int,input().split()))
Katanas = [list(map(int,input().split())) for x in range(Num)]

amax = max([x[0] for x in Katanas])
bpower = sorted([x[1] for x in Katanas if x[1] > amax],reverse=True)
bsum = sum(bpower)
if bsum > HP:
    attake = 0
    while HP > 0:
        attake += 1
        HP -= bpower[0]
        bpower = bpower[1:]
else:
    attake = math.ceil((HP-bsum)/amax)+len(bpower)
print(attake)