import math

N, H = map(int, input().split())
A = []
B = []

for i in range(N):
    a, b = map(int, input().split())
    A.append(a)
    B.append(b)

A.sort()
A = A[::-1]
a_max = A[0]

B.sort()
B = B[::-1]

attack = 0
idx = 0

while B[idx] > a_max:
    H -= B[idx]
    attack += 1
    idx += 1
    if H <= 0:
        print(attack)
        break

if H > 0:
    attack += math.ceil(H / a_max)
    print(attack)