import math

inn = [int(x) for x in input().split()]
aa = []
bb = []
for i in range(inn[0]):
    tmp = [int(x) for x in input().split()]
    aa.append(tmp[0])
    bb.append(tmp[1])

count = 0
tot = 0
if min(bb) <= max(aa):
    for b in sorted(bb, reverse=True):
        if b <= max(aa):
            count += math.ceil((inn[1]-tot)/max(aa))
            tot = inn[1]
            print(count)
            exit()
        tot += b
        count += 1
        if tot >= inn[1]:
            print(count)
            exit()
else:
    tot = sum(bb)
    count = inn[0]

if tot >= inn[1]:
    print(count)
else:
    count = inn[0] + math.ceil((inn[1]-sum(bb))/max(aa))
    print(count)
