import numpy as np
import math
import sys
n, h = map(int, input().split())
A = np.array([])
B = np.array([])
for _ in range(n):
    a, b = map(int, input().split())
    A = np.append(A, a)
    B = np.append(B, b)

max_a = A.max()
  
C = B[max_a <= B][::-1]

cnt = 0
for c in C:
    if h <= 0:
        break
    cnt += 1
    h -= c

if h > 0:
    cnt += math.ceil(h / max_a)

print(cnt)