Problem:
Score : 400 points

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.

Sample Input 1

25

Sample Output 1

17

The following 17 pairs satisfy the condition: (1,1), (1,11), (2,2), (2,22), (3,3), (4,4), (5,5), (6,6), (7,7), (8,8), (9,9), (11,1), (11,11), (12,21), (21,12), (22,2), and (22,22).

Sample Input 2

1

Sample Output 2

1

Sample Input 3

100

Sample Output 3

108

Sample Input 4

2020

Sample Output 4

40812

Sample Input 5

200000

Sample Output 5

400000008

Solution in JavaScript (node.js v5.12) (judge verdict: Time Limit Exceeded)

'use strict'

function Main(input) {

  input = input.trim()
  const N = parseInt(input)

  let c = 0
  for(let i = 1; i <= N; ++i) {
    const a = `${i}`
    for(let j = 1; j <= N; ++j) {
      const b = `${j}`

      const al = a[a.length - 1]
      const bt = b[0]

      const at = a[0]
      const bl = b[b.length - 1]

      if (al === bt && at === bl) c++


    }
  }

  console.log(c)
 
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));