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