n, h = input().split()
n = int(n)
h = int(h)

a = []
b = []
for i in range(n):
    a_, b_ = input().split()
    a.append(int(a_))
    b.append(int(b_))

import numpy as np
a = np.array(a)
b = np.array(b)

to_throw = b[b>max(a)]
sum_throw = sum(to_throw)

d = h - sum_throw

if d <= 0:
    cum = np.cumsum(np.sort(b)[::-1])
    print(len(to_throw) - len(cum[cum>=h]) + 1)
else:
    import math
    print(len(to_throw) + math.ceil(d/max(a)))
