from bisect import bisect_right
N = int(input())
material = [1]
diff = 2
for i in range(10000):
    sub = material[-1] + diff
    if sub > 10**7:
        break
    material.append(sub)
    diff += 1

nokori = N
cnt = 0
while nokori > 0:
    idx = bisect_right(material, nokori) - 1
    price = material[idx]
    nokori -= price
    cnt += 1
print(cnt)