import sys
from math import ceil
input = sys.stdin.readline
n, h = map(int, input().split())
a, b = [0]*n, [0]*n
for i in range(n):
    aa, bb = map(int, input().split())
    a[i], b[i] = aa, bb
a_max = max(a)
b_thr = []
for i in b:
    if i > a_max:
        b_thr.append(i)
ans = 0
for i in b_thr:
    if h > 0:
        h -= i
        ans += 1
    else:
        print(ans)
        exit()
ans += ceil(h/a_max)
print(ans)