output_description: Print the answer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: S = list(map(int, input().split()))
  a = [S[1]]
  for i in range(0, S[0] - 1):
      while a[i] > 2 * S[2]:
          a[i] = a[i] - S[2]
  a.append(((a[i]) ** 2) % S[2])
  print(sum(a))
  
problem_description: Statement
  
  Given is a positive integer N. How many tuples (A,B,C) of positive integers
  satisfy A \times B + C = N?
samples: [{"input": "3", "output": "3\n    \n\nThere are 3 tuples of integers that satisfy A \\times B + C = 3: (A, B, C) =\n(1, 1, 2), (1, 2, 1), (2, 1, 1).\n\n* * *"}, {"input": "100", "output": "473\n    \n\n* * *"}, {"input": "1000000", "output": "13969985"}]