#include <iostream>

using namespace std;

class Point3D {

private:

double x;

double y;

double z;

public:

Point3D() {x = 0.0; y = 0.0; z = 0.0;}

Point3D(double X, double Y, double Z) {x = X; y = Y; z = Z;}

Point3D(const Point3D& P) {x = P.x; y = P.y; z = P.z;}

Point3D projX(const Point3D&