Let us denote the sum of digits of the number *N* by S(*N*). In this problem, we want you to determine, how often the following equality holds:

### Input

The input contains a single integer *K*, 2 ≤ *K* ≤ 50.

### Output

You should output the number of pairs of

*K*-digit numbers

*A* and

*B* to satisfy the above equality. Counting that number you should be aware of the following:

- numbers
*A* and *B* should not have leading zeroes;
- while counting the total number of pairs, the order of numbers
*A* and *B* matters, thus, for instance, (12, 26) and (26, 12) are different pairs that satisfy the conditions of the problem.

### Sample

**Problem Author: **Leonid Volkov

**Problem Source: **USU Internal Contest, March 2002