import java.util.Scanner;

public class ComputePI {

    public static void main(String[] args) {

        System.out.print( "Please enter the amount of  "
                + "digits of PI, you would like to set it too");
        Scanner termScan = new Scanner( System.in );
        int term = termScan.nextInt();
        termScan.close();
        double pi = 3.0;
        int loopCount = 2;
        int number = 2;


            while ( loopCount <= term )
            {
                    if (loopCount % 2 == 0)
                {
                    pi = pi + ( 4.0/ ((number)*(number+1)*(number+2)) );
                }
                else
                {
                    pi = pi - ( 4.0 / ((number)*(number+1)*(number+2)));
                }

                number = number + 2;

                loopCount++;
                continue;
            }



        System.out.print( "The Value of Pi in " + term +
                    " terms is equal to " + pi);
    }

}