output_description: Print the answer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: import sys
  
  stdin = sys.stdin
  
  ni = lambda: int(ns())
  na = lambda: list(map(int, stdin.readline().split()))
  ns = lambda: stdin.readline().rstrip()  # ignore trailing spaces
  
  n = ni()
  ct = 0
  for i in range(1, n + 1):
      head = i % 10
      if head == 0:
          continue
      k = i
      tail = 0
      while k > 0:
          tail = k % 10
          k //= 10
      if head == tail:
          if head <= n:
              ct += 1
      # (head)...(tail)
      d = 10
      while d <= n:
          # head*d + tail
          if n >= (head + 1) * d:
              ct += d // 10
          elif n < head * d:
              pass
          else:
              ct += (n - head * d - tail + 10) // 10
          d *= 10
  print(ct)
  
problem_description: 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.
samples: [{"input": "25", "output": "17\n    \n\nThe following 17 pairs satisfy the condition: (1,1), (1,11), (2,2), (2,22),\n(3,3), (4,4), (5,5), (6,6), (7,7), (8,8), (9,9), (11,1), (11,11), (12,21),\n(21,12), (22,2), and (22,22).\n\n* * *"}, {"input": "1", "output": "1\n    \n\n* * *"}, {"input": "100", "output": "108\n    \n\n* * *"}, {"input": "2020", "output": "40812\n    \n\n* * *"}, {"input": "200000", "output": "400000008"}]