import math

n, h = map(int, input().split())
a, b = [0] * n, [0] * n
for i in range(n):
    a[i], b[i] = map(int, input().split())

amax = max(a)
cnt = 0
for bi in sorted(b, reverse=True):
    if bi < amax:
        break
    cnt += 1
    h -= bi
    if h <= 0:
        break

if h > 0:
    cnt += math.ceil(h / amax)

print(cnt)