# "Mirror prime" numbers

Easy

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

We will call a number "mirror prime", if it is prime, and the number written in a reverse order is also prime.

Find the number of "mirror primes" from a to b.

## Input

Two integers a and b (1 ≤ a ≤ b ≤ 10000).

## Output

Print the number of "mirror primes" from a to b inclusive.

## Examples

Input #1

Answer #1

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