private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) { //úprava 1. rovnice
        MatrixEntering me = new MatrixEntering(m1);
        me.setModal(true);
        me.setVisible(true);
        jPanel21.removeAll();
        m3=me.getM();
        if(m3.matice!=null)
            m1 = m3;
        m1.vypis(jPanel21);
        jPanel11.updateUI();
        pack();
    }