Practice Optimization and Number theory with the exercise "Number of Digits"

Learning Opportunities

This puzzle can be solved using the following concepts. Practice using these concepts and improve your skills.

Count the number of times the digit k appears in all non-negative integers less than or equal to a given integer n.

Input

Line 1: A single integer n, the upper bound for counting occurrences of the digit k.
Line 2: A single integer k.

Output

Line 1 : A single integer representing the total number of times the digit k appears in all non-negative integers less than or equal to n.

Constraints

0 ≤ n ≤ 10^9
1 ≤ k ≤ 9

Example

Input

12
2

Output

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