from bisect import bisect_left
import math
N,H = map(int,input().split())
A = [0]*N
B = [0]*N

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

A = sorted(A)
B = sorted(B)

damage = 0
count = 0
b = bisect_left(B,A[-1])
damage = sum(B[b:])
count += len(B[b:])
count += math.floor((H-damage)/A[-1])
damage = H - (H-damage)%A[-1]
if damage == H:
  pass
else:
  count += 1
print(count)