import sys
from math import ceil
input = sys.stdin.readline
n, h = map(int, input().split())
l = []
a_max = 0
for i in range(n):
    a, b = map(int, input().split())
    if i == 0:
        a_max = a
        if a_max < b:
            l.append(b)
    else:
        if a_max < a:
            a_max = a
        if a_max < b:
            l.append(b)
l.sort(reverse=True)
ans = 0
for i in l:
    if i > a_max:
        h   -= i
        ans += 1
    else:
        break
ans += ceil(h/a_max)
print(ans)