Numbers

There was nothing to do, it was in the evening ... Since Timur has a big team and a lot of paper, the work was found.

Take the number a. Take the number b. And write down all the numbers from a to b. Calculate the sum of all written digits.

Input

Two positive integers a and b (a ≤ b). The numbers do not exceed 10^12.

Output

Print the sum of all written digits.

Examples