DWITE Online Computer Programming Contest, February 2006, Problem 5

The number ~181~ is a prime palindrome because it is both a prime number and a palindrome. A palindrome is a number that is the same when read forward as backward. Write a program that determines how many prime palindromes there are between two numbers.

The input will contain five sets of data. Each set will contain two integers, ~L~ and ~U~, the range of numbers to determine the prime palindromes. ~2 \le L \le U \le 999\,999~.

The output will contain the number of prime palindromes between ~L~ and ~U~, inclusive.

Sample Input (3 sets of data only)

2 10
100 200
10000 20000

Sample Output

4
5
26