class Triangle
{	
	private int n;	
	private int answer = 0;	
	Triange(int n){this.n = n;}		
	
	public static void main(String[] args)
	{		
		Triangle t = new Triangle(3);		
		System.out.println(t.tri());	
	}		

	public tri()
	{		
		triHelper();		
		return answer;	
	}		

	private int triHelper()
	{ 				
		// Note that the base case is to do nothing  		
		if (n > 0)
		{   			
			answer = answer + n;			
			n = n - 1;			
			tryHelper();    		 
		}	
	}
}