N, H = map(int, input().split())
a = [0] * N
b = [0] * N
for i in range(N):
	a[i], b[i] = map(int, input().split())
a_max = max(a)
ans = dmg = 0
for dmg_i in sorted([bi for bi in b if bi > a_max], reverse=True):
	dmg += dmg_i
	ans += 1
	if dmg >= H:
		print(ans)
		break
else:
	print(ans + (H - dmg + a_max - 1) // a_max)
