Mimi has just won two raffle tickets for the Polar Express! Unfortunately, there is just one obstacle in the way — the skill testing question!

Let us define ~\operatorname S(x)~ to be the sum of digits of ~x~. Given two positive integers, ~L~ and ~R~, compute the number of distinct values of ~\operatorname S(x)~, for ~x = L, L+1, \dots, R~.

Mimi has agreed to give you the other ticket if you help her solve this problem. Can you do it?

Constraints

Subtask 1 [10%]

~1 \le L \le R \le 10^5~

Subtask 2 [90%]

~1 \le L \le R \le 10^{18}~

Input Specification

The first and only line of input will contain two space separated integers, ~L~ and ~R~.

Output Specification

A single integer, the number of distinct values of ~\operatorname S(x)~.

Sample Input

19 28

Sample Output

9