Number of N-digit numbers containing the digit 7
Very easy
Execution time limit is 1 second
Runtime memory usage limit is 64 megabytes
Find K - number of N-digit natural numbers, which contain in their records at least one digit 7.
Input
The only positive integer N (1 ≤ N ≤ 10).
Output
The desired number K.
Examples
Input #1
Answer #1
Submissions 3K
Acceptance rate 30%