Problem:
Score : 200 points

Problem Statement

Find the number of palindromic numbers among the integers between A and B (inclusive).
Here, a palindromic number is a positive integer whose string representation in base 10 (without leading zeros) reads the same forward and backward.

Constraints

10000 \leq A \leq B \leq 99999

All input values are integers.

Input

Input is given from Standard Input in the following format:

A B

Output

Print the number of palindromic numbers among the integers between A and B (inclusive).

Sample Input 1

11009 11332

Sample Output 1

4

There are four integers that satisfy the conditions: 11011, 11111, 11211 and 11311.

Sample Input 2

31415 92653

Sample Output 2

612

Solution in OCaml (4.02.3) (judge verdict: Accepted)

(* O(b log b) *)
Scanf.scanf "%d %d" @@ fun a b ->
  let string_rev s = let n = String.length s in String.init n @@ fun i -> s.[n - i - 1] in
  let ans = ref 0 in
  for n = a to b do
    let s = string_of_int n in
    if string_rev s = s then incr ans
  done;
  Printf.printf "%d\n" !ans