from bisect import bisect_right
from math import ceil

n, hp = map(int, input().split())
A = []
B = []
for _ in range(n):
    a, b = map(int, input().split())
    A.append(a)
    B.append(b)
MAX_A = max(A)
B.sort()

cnt = 0
damage = 0
throws = B[bisect_right(B, MAX_A):]
cnt += len(throws)
hp -= sum(throws)
cnt += ceil(hp / MAX_A)
print(cnt)
