import java.io.*;
class Modified4Vectors
{
    static BufferedReader keyboard = new
    BufferedReader (new InputStreamReader(System.in));
    static PrintWriter screen = new PrintWriter( System.out, true);

    //Absolute Momentum class
    private static double getMom(double px, double py, double pz)
    {
        double Mom;
        Mom = Math.sqrt((px*px)+(py*py)+(pz*pz));
        return Mom;
    }

    //Invariant Mass class
    private static double getInv(double energy, double momentum)
    {
        double Inv;
        Inv = Math.sqrt((energy*energy)-(momentum*momentum));
        return Inv;
    }

    //Add vectors
    private static double[] getInv(double e1, double p1, double p2, double p3, double e2, double p4, double p5, double p6)
    {
        double [] thirdvector = new double[4];
        thirdvector[0] = e1 + e2;
        thirdvector[1] = p1 + p4;
        thirdvector[2] = p2 + p5;
        thirdvector[3] = p3 + p6;

        return thirdvector[];
    }
    //Main method
    public static void main (String [] args) throws IOException

    {
       int compMax = 4;

       double [] particle1 = new double[compMax];
       double [] particle2 = new double[compMax];
       double mom1;
       double mom2;
       double inv1;
       double inv2;
       double [] particle3 = new double[compMax];

       //4Vector 1 loop
       for (int p1n = 0; p1n < compMax; p1n++)
       {
           screen.println("Please enter component " + (p1n+1) + " of the first four vector.");
           particle1[p1n] = new Double(keyboard.readLine()).doubleValue();

        }

        //4Vector 2 loop
           for (int p2n = 0; p2n < compMax; p2n++)
       {
           screen.println("Please enter component " + (p2n+1) + " of the first four vector.");
           particle2[p2n] = new Double(keyboard.readLine()).doubleValue();

        }

        mom1 = getMom(particle1[1],particle1[2],particle1[3]);
        screen.println("The absolute momentum of the first vector is " + mom1);
        mom2 = getMom(particle2[1],particle2[2],particle2[3]);
        screen.println("The absolute momentum of the second vector is " + mom2);

        inv1 = getInv(particle1[0],mom1);
        screen.println("The invariant mass related to the first vector is " + inv1);
        inv2 = getInv(particle2[0],mom2);
        screen.println("The invariant mass related to the second vector is " + inv1);

        particle3 = getInv(particle1[0],particle1[1],particle1[2],particle1[3],particle2[0],particle2[1],particle2[2],particle2[3]);
        for( int n = 0; n < 4; n++)
        {
            screen.println( n + " location, value stored = " + particle3[n] );

    }
}
}