import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

import itertools
from math import ceil

n, h = map(int, readline().split())
a = [0] * n
b = [0] * n
for i in range(n):
    a[i], b[i] = map(int, readline().split())
max_a = max(a)
b.sort(reverse=True)
cnt = [0] * (n + 1)
cumsum = [0] + list(itertools.accumulate(b))
for i in range(n + 1):
    cnt[i] = i + ceil((h - cumsum[i]) / max_a)
print(min(cnt))
