import operator as op
import math

N, H = list(map(int, input().split()))
ab = []
max_a = 0
for i in range(N):
    ab.append([int(i) for i in input().split()])
    max_a = max(max_a, ab[i][0])
ab.sort(key=op.itemgetter(1), reverse=True)
ans = 0
for i in ab:
    if H < 0:
        print(ans)
        break
    if i[1] < max_a:
        print(ans + math.ceil(H / max_a))
        break
    H -= i[1]
    ans += 1
