text: #include"mylib.h"
  #include<iostream>
  
  using namespace std;
  
  int f(int n, int s)
  {
  	if (n <= 1)
  	{
  		return s;
  	}
  	else if (n % 2 == 0)
  	{
  		return f(n / 2, ++s);
  	}
  	else
  	{
  		return f(3 * n + 1, ++s);
  	}
  }
  
  void circle(int r)
  {
  	if (r == 0)
  	{
  		cout << "*";
  	}
  	else
  	{
  		for (int i = 0; i <= 2 * r; ++i)
  		{
  			int j = 0;
  
  			while ((i - r) * (i - r) + (j - r) * (j - r) > (r * r))
  			{
  				++j;
  				cout << "  ";
  			}
  			cout << "*";
  
  			while ((i - r) * (i - r) + (j - r) * (j - r) <= (r * r))
  			{
  				++j;
  				cout << "  ";
  			}
  			cout << "*" << endl;
  		}
  	}
  }