write a go solution for Description:
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>=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<=a_i<=b_i holds for every 1<=i<=m.

Developers say that production costs are proportional to sum_i=1^mb_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.

Input Format:
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*10^6. The integer does not contain leading zeros.

Output Format:
Print one number — minimal value of sum_i=1^mb_i.

Note:
None. Output only the code with no comments, explanation, or additional text.