A11829. Perfect Encoding

You are working as an analyst in a company working on a new system for big data storage. This system will store $n$ different objects. Each object should have a unique ID.

To create the system, you choose the parameters of the system — integers $m \ge 1$ and $b_{1}, b_{2}, \ldots, b_{m}$ . With these parameters an ID of some object in the system is an array of integers $[a_{1}, a_{2}, \ldots, a_{m}]$ where $1 \le a_{i} \le b_{i}$ holds for every $1 \le i \le m$ .

Developers say that production costs are proportional to $\sum_{i=1}^{m} b_{i}$ . You are asked to choose parameters $m$ and $b_{i}$ so that the system will be able to assign unique IDs to $n$ different objects and production costs are minimized. Note that you don't have to use all available IDs.

In the only line of input there is one positive integer $n$ . The length of the decimal representation of $n$ is no greater than $1.5 \cdot 10^{6}$ . The integer does not contain leading zeros.

Print one number — minimal value of $\sum_{i=1}^{m} b_{i}$ .