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## 1206. Sum of Digits of the Sum of Numbers

Time limit: 1.0 second
Memory limit: 64 MB
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:
S(A + B) = S(A) + S(B)

### 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:
1. numbers A and B should not have leading zeroes;
2. 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

inputoutput
```2
```
```1980
```
Problem Author: Leonid Volkov
Problem Source: USU Internal Contest, March 2002
Tags: none