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)
attake=0
while HP > 0:
    attake += 1
    HP -= bpower[0]
    bpower = bpower[1:]
else:
    attake += math.ceil(HP/amax)
print(attake)