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 Ruby (2.3.3) (judge verdict: Accepted)

def digits_of(num)
  num.to_s.chars.reverse!.map(&:to_i)
end

def palindrome?(num)
  ds = digits_of(num)
  ds.size.times do |i|
    if ds[i] != ds[-(i + 1)]
      return false
    end
  end

  true
end

a, b = gets.split.map(&:to_i)

puts a.upto(b).count { |n| palindrome?(n) }