N = int(input())
cnt = [N+1] * (N+1)

i = 1
add = 1
while i <= N:
    cnt[i] = 1
    for j in range(1, i + 1):
        if i + j > N:
            break
        cnt[i+j] = min(cnt[i+j], cnt[j] + 1)
    add += 1
    i += add

print(cnt[N])