CSES - Counting Numbers
  • Time limit: 1.00 s
  • Memory limit: 512 MB
Your task is to count the number of integers between $a$ and $b$ where no two adjacent digits are the same.

Input

The only input line has two integers $a$ and $b$.

Output

Print one integer: the answer to the problem.

Constraints
  • $0 \le a \le b \le 10^{18}$
Example

Input:
123 321

Output:
171