Problem Statement

Given is a positive integer $N$. Find the number of pairs $(A, B)$ of positive integers not greater than $N$ that satisfy the following condition:

• When $A$ and $B$ are written in base ten without leading zeros, the last digit of $A$ is equal to the first digit of $B$, and the first digit of $A$ is equal to the last digit of $B$.

Constraints

• $1 \leq N \leq 2 \times 10^5$
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer.