Problems
"Mirror prime" numbers
"Mirror prime" numbers
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 data
Two integers a and b (1 ≤ a ≤ b ≤ 10000).
Output data
Print the number of "mirror primes" from a to b inclusive.
Examples
Input example #1
10 25
Output example #1
3