import math
n,h = map(int,input().split())
a = []
b = []
for i in range(n):
  x,y = map(int, input().split())
  a += [x]
  b += [y]
amax = max(a)
ans = 0
for x in b:
  if x >= amax:
    ans += 1
    h -= x
  if h <= 0:
    print(ans)
    exit()
 
if h % amax == 0:
  print(ans + h//amax)
else:
  print(ans + h//amax + 1)