P1925 最大划分乘积

欧拉工程183题 有改动

Let $N$ be a positive integer and let $N$ be split into $k$ equal parts, $r = N/k$, so that $N = r + r + ... + r$. Let $P$ be the product of these parts, $P = r ×r × ... × r = rk$. For example, if $11$ is split into five equal parts, $11 = 2.2 + 2.2 + 2.2 + 2.2 + 2.2$, then $P = 2.2^5 = 51.53632$. Let $M(N) = P_{\max}$ for a given value of $N$. It turns out that the maximum for $N = 11$ is found by splitting eleven into four equal parts which leads to $P_{max} = (11/4)^4$; that is, $M(11) = 14641/256 = 57.19140625$, which is a terminating decimal. However, for $N = 8$ the maximum is achieved by splitting it into three equal parts, so $M(8) = 512/27$, which is a non-terminating decimal. Let $D(N) = N$ if $M(N)$ is a non-terminating decimal and $D(N) = -N$ if $M(N)$ is a terminating decimal.

Input a positive integer $a(5≤a≤32767)$.

Output the value of $D(5)+D(6)+...+D(a)$.