output_description: For each dataset, prints the number of prime numbers.
input_description: Input consists of several datasets. Each dataset has an integer n (1 ≤ n ≤
  999,999) in a line.
  
  The number of datasets is less than or equal to 30.
attempt: A = [
      960131,
      960137,
      960139,
      960151,
      960173,
      960191,
      960199,
      960217,
      960229,
      960251,
      960259,
      960293,
      960299,
      960329,
      960331,
      960341,
      960353,
      960373,
      960383,
      960389,
      960419,
      960467,
      960493,
      960497,
      960499,
      960521,
      960523,
      960527,
      960569,
      960581,
      960587,
      960593,
      960601,
      960637,
      960643,
      960647,
      960649,
      960667,
      960677,
      960691,
      960703,
      960709,
      960737,
      960763,
      960793,
      960803,
      960809,
      960829,
      960833,
      960863,
      960889,
      960931,
      960937,
      960941,
      960961,
      960977,
      960983,
      960989,
      960991,
      961003,
      961021,
      961033,
      961063,
      961067,
      961069,
      961073,
      999149,
      999169,
      999181,
      999199,
      999217,
      999221,
      999233,
      999239,
      999269,
      999287,
      999307,
      999329,
      999331,
      999359,
      999371,
      999377,
      999389,
      999431,
      999433,
      999437,
      999451,
      999491,
      999499,
      999521,
      999529,
      999541,
      999553,
      999563,
      999599,
      999611,
      999613,
      999623,
      999631,
      999653,
      999667,
      999671,
      999683,
      999721,
      999727,
      999749,
      999763,
      999769,
      999773,
      999809,
      999853,
      999863,
      999883,
      999907,
      999917,
      999931,
      999953,
      999959,
      999961,
      999979,
      999983,
  ]
  while True:
      try:
          n = int(input())
          print(A)
      except:
          break
  
problem_description: Prime Number
  
  Write a program which reads an integer n and prints the number of prime
  numbers which are less than or equal to n. A prime number is a natural number
  which has exactly two distinct natural number divisors: 1 and itself. For
  example, the first four prime numbers are: 2, 3, 5 and 7.
samples: [{"input": "3\n    11", "output": "2\n    5"}]