//calculating PI
		
		double sum=0;
		double adder=0;
		for (int i=0; i<2000000;i++)  //the more, the more exact
		{
			adder+=1;
			sum+=(1/(adder*adder));
		}
		
		sum = sum*6;
		sum=Math.sqrt(sum);  //quare root, the result is PI !!

		System.out.println("Pi is:"+sum);