How many numbers#8381

How many numbers

1 second

128 megabytes

Easy

At the faculty of mathematics, Orhan was faced with the following problem: find the number of positive integers from $1$ to $1 0^{n}$ 10^n, in which all digits are different.

Since Orhan also goes to computer science classes at FizMat Lyceum, he easily wrote a program that calculates the answer. And can you do it?

Input

One integer $n (1 \leq n \leq 18)$ n~(1 \le n \le 18).

Output

Print the number of required positive integers.

Examples

Example 1

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Example 2

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1 0^{n}

n (1 \leq n \leq 18)