Valid Kingdom Sequence

You are given a sequence of digits. You need to determine whether this sequence is valid based on the following kingdom rules:

• The sequence must not start with a '0'.
• The length of the sequence must be a prime number. In mathematical terms, if we denote the length by \(L\), then \(L\) must be a prime number.
• The sequence must not be a palindrome, i.e. it should not read the same forwards and backwards.

If all these conditions are satisfied, output VALID; otherwise, output INVALID.

Example:

Input: 239
Output: VALID
Input: 12321
Output: INVALID

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inputFormat

The input consists of a single line containing the sequence of digits. The sequence is provided via standard input.

Constraints: The sequence is non-empty and consists only of digit characters.

outputFormat

Output a single line to standard output with the word VALID if the sequence meets all the specified rules, or INVALID otherwise.

## sample

239

VALID