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]
C = list(np.sort(B))

ans = 0
while h > 0:
    if C != []:
        atack = C.pop()
    else:
        ans += math.ceil(h / max_a)
        print(ans)
        sys.exit()
    h -= atack
    ans += 1

print(ans)
