## Editorial for An Animal Contest 3 P2 - Monkey Potato

Remember to use this editorial

**only**when stuck, and**not to copy-paste code from it**. Please be respectful to the problem author and editorialist.**Submitting an official solution before solving the problem yourself is a bannable offence.**Author:

Denote to be the set of all valid digits given in input.

#### Subtask 1

For this subtask, notice that we can take the smallest digit in and output it times.

**Time Complexity**:

#### Subtask 2

Consider cases:

:

- No valid integer can be formed with the digit , so
`-1`

should be outputted.

- No valid integer can be formed with the digit , so
:

Let the second smallest digit in be .

- The smallest palindrome consists of 's.

- A length palindrome can be constructed with the form: .

:

- Let the smallest digit in be . The length palindrome is: .

**Time Complexity**:

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