import math
N, H = map(int, input().split())
S = [[int(i) for i in input().split()] for j in range(N)]
S.sort()

Use = []
for i in range(N-1):
    if S[i][1] > S[-1][0]:
        Use.append(S[i][1])
Use.sort(reverse = True)

i = 0
HP = H
while HP > 0 and i < len(Use):
    HP -= Use[i]
    i += 1

if HP <= 0:
    print(i)
elif i == len(Use):
    if S[-1][1] >= HP:
        print(i+1)
    else:
        extra = int(math.ceil((HP- S[-1][1])/S[-1][0]))
        print(i+1+extra)