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:
    for x in range(len(bpower)):
        if sum(bpower[:x]) > HP:
            print(x+1)
            exit()
attake = math.ceil((HP-bsum)/amax)+len(bpower)
print(attake)