private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) { //úprava 2. rovnice
        MatrixEntering me = new MatrixEntering(m2);
        me.setModal(true);
        me.setVisible(true);
        jPanel22.removeAll();
        m3=me.getM();
        if(m3.matice!=null)
            m2 = m3;
        m2.vypis(jPanel22);
        jPanel12.updateUI();
        pack();
    }