from operator import itemgetter
import math

n, h = map(int, input().split())
ab = []
A = 0
B = 1
for i in range(n):
    ab.append(list(map(int, input().split())))

ab.sort(key=itemgetter(B), reverse=True)

sumB = 0
for _ab in ab:
    sumB += _ab[B]

ans = 0
damage = 0
i = 0
while damage < h and ans < n:
    damage += ab[ans][B]
    ans += 1

ab.sort(key=itemgetter(A), reverse=True)

if damage < h:
    ans += math.ceil((h - damage)/ab[0][A])

print(ans)