Codeforces-962C-Make a Square（暴力二进制枚举）

C. Make a Square

time limit per test：2 seconds

memory limit per test：256 megabytes

input：standard input

output：standard output

You are given a positive integer $n$, written without leading zeroes (for example, the number 04 is incorrect).

In one operation you can delete any digit of the given integer so that the result remains a positive integer without leading zeros.

Determine the minimum number of operations that you need to consistently apply to the given integer $n$ to make from it the square of some positive integer or report that it is impossible.

An integer $x$ is the square of some positive integer if and only if $x$