n,h = map(int,input().split())
lst = []
amax = 0
for i in range(n):
    a,b = map(int,input().split())
    amax = max(amax,a)
    lst.append([a,b])
lst.sort(key = lambda x:x[1],reverse = True)

dmg = 0
cnt = 0
for i in range(n):
    cnt += 1
    dmg += lst[i][1]
    if dmg >= h:
      print(cnt)
      exit()
else:
    if (h-dmg)%a==0:
        print(cnt + (h-dmg)//a)
    else:
        print(cnt + (h-dmg)//a + 1)