Count Palindromic Numbers in an Interval

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

A non-negative integer is palindromic if its decimal digits read the same left to right and right to left. For example, $0$, $7$, $11$, and $121$ are palindromic, but $12$ and $120$ are not. Given integers $L$ and $R$ with $L\le R$, count palindromic integers in the inclusive interval $[L,R]$. Zero is palindromic.

Input

One line contains two integers $L$ and $R$, in this order.

Output

Print one integer: the count of palindromic integers in $[L,R]$.

Subtasks

• Subtask 1 (20%): $0\le L\le R\le 1000$.
• Subtask 2 (30%): $0\le L\le R\le 10000$.
• Subtask 3 (50%): $0\le L\le R\le 200000$.

Examples

Example 1

Input:

0 11

Output:

11

Explanation: The ten values 0 through 9 are palindromic. 10 is not; 11 is. Therefore the total is 10 + 1 = 11.

Example 2

Input:

120 123

Output:

1

Explanation: Reversing 120, 121, 122 and 123 gives 21, 121, 221 and 321. Only 121 is palindromic, so the answer is 1.

Example 3

Input:

0 0

Output:

1

Explanation: The interval contains only zero, whose single digit is unchanged when reversed. The answer is 1.