comefrom: <doocs>0204.Count Primes_1.py
code: def countPrimes( n: int) -> int:
      primes = [True] * n
      ans = 0
      for i in range(2, n):
          if primes[i]:
              ans += 1
              for j in range(i + i, n, i):
                  primes[j] = False
      return ans
masked: def sample_funcname ( var_0 : int ) -> int :
      var_3 = [ True ] * var_0
      var_5 = 0
      for var_8 in range ( 2 , var_0 ) :
          if var_3 [ var_8 ] :
              var_5 += 1
              for var_10 in range ( var_8 + var_8 , var_0 , var_8 ) :
                  var_3 [ var_10 ] = False
      return var_5
  