diff --git a/Calculator.java b/Calculator.java
index 7070c87..c43ca9f 100644
--- a/Calculator.java
+++ b/Calculator.java
@@ -1,14 +1,30 @@
+import java.util.Scanner;
+
 public class Calculator {
     public static void main(String[] args) {
-        GFrame frame = new GFrame("Calculator");
-        String expr = "(84 / 4 * 3 - 9) * 2 + 1 / 5"; // 108.2
+        // String expr = "(84 / 4 * 3 - 9) * 2 + 1 / 5"; // 108.2
+        String expr = new String(" ");
+        Scanner sc = new Scanner(System.in);
         Parser p;
+
         if (args.length == 0) {
-            p = new Parser(expr);
+            new GFrame("Calculator");
         } else {
-            p = new Parser(args[0]);
+            if (args[0].equals("-n")) {
+                System.out.println("Type \"exit\" or Ctrl+C to exit.");
+                while (true) {
+                    System.out.print(">>> ");
+                    expr = sc.nextLine();
+                    if (!expr.equals("exit")) {
+                        p = new Parser(expr);
+                        System.out.println(p.eval());
+                    } else {
+                        sc.close();
+                        break;
+                    }
+                }
+            } else {
+            }
         }
-        System.out.println("postfix => \t " + p.getPostfix());
-        System.out.println(p.eval());
     }
 }
diff --git a/GFrame.java b/GFrame.java
index 4ba0a82..14feb30 100644
--- a/GFrame.java
+++ b/GFrame.java
@@ -93,7 +93,7 @@ public class GFrame extends JFrame {
         JButton bClear = newButton("CL", 180, 100, 60, 40);
         JButton bAdd = newButton("+", 250, 300, 100, 40);
         JButton bSub = newButton("-", 250, 250, 100, 40);
-        JButton bMul = newButton("X", 250, 200, 100, 40);
+        JButton bMul = newButton("x", 250, 200, 100, 40);
         JButton bDiv = newButton("%", 250, 150, 100, 40);
         JButton bCut = newButton("", 180, 300, 60, 40);
         bCut.setFont(new Font("JetBrainsMono Nerd Font", Font.PLAIN, 20));
@@ -158,7 +158,6 @@ public class GFrame extends JFrame {
                     Vector<String> s = history.getHistory();
                     s.add(expression + " = " + formattedResult);
                     for (int i = 0; i < s.size(); i++) {
-                        System.out.println(s.get(i));
                         // tHist.setText(new String(s.get(i).concat(tHist.getText())).concat("\n"));
                         tHist.append(s.get(i));
                         tHist.append("\n");
diff --git a/SteelCheckBox.java b/SteelCheckBox.java
new file mode 100644
index 0000000..6732c26
--- /dev/null
+++ b/SteelCheckBox.java
@@ -0,0 +1,82 @@
+public class SteelCheckBox extends javax.swing.JCheckBox
+{
+    // <editor-fold defaultstate="collapsed" desc="Variable declaration">
+    private boolean colored = false;
+    private boolean rised = false;
+    private eu.hansolo.tools.ColorDef selectedColor = eu.hansolo.tools.ColorDef.JUG_GREEN;
+    protected static final String COLORED_PROPERTY = "colored";
+    protected static final String COLOR_PROPERTY = "color";
+    protected static final String RISED_PROPERTY = "rised";
+    // </editor-fold>
+
+    // <editor-fold defaultstate="collapsed" desc="Constructor">
+    public SteelCheckBox()
+    {
+        super();
+        setPreferredSize(new java.awt.Dimension(100, 26));
+    }
+    // </editor-fold>
+
+    // <editor-fold defaultstate="collapsed" desc="Getter/Setter">
+    public boolean isColored()
+    {
+        return this.colored;
+    }
+
+    public void setColored(final boolean COLORED)
+    {
+        final boolean OLD_STATE = this.colored;
+        this.colored = COLORED;
+        firePropertyChange(COLORED_PROPERTY, OLD_STATE, COLORED);
+        repaint();
+    }
+
+    public boolean isRised()
+    {
+        return this.rised;
+    }
+
+    public void setRised(final boolean RISED)
+    {
+        final boolean OLD_VALUE = this.rised;
+        this.rised = RISED;
+        firePropertyChange(RISED_PROPERTY, OLD_VALUE, RISED);
+    }
+
+    public eu.hansolo.tools.ColorDef getSelectedColor()
+    {
+        return this.selectedColor;
+    }
+
+    public void setSelectedColor(final eu.hansolo.tools.ColorDef SELECTED_COLOR)
+    {
+        final eu.hansolo.tools.ColorDef OLD_COLOR = this.selectedColor;
+        this.selectedColor = SELECTED_COLOR;
+        firePropertyChange(COLOR_PROPERTY, OLD_COLOR, SELECTED_COLOR);
+        repaint();
+    }
+
+    @Override
+    public void setUI(final javax.swing.plaf.ButtonUI BUI)
+    {
+        super.setUI(new SteelCheckBoxUI(this));
+    }
+
+    public void setUi(final javax.swing.plaf.ComponentUI UI)
+    {
+        this.ui = new SteelCheckBoxUI(this);
+    }
+
+    @Override
+    protected void setUI(final javax.swing.plaf.ComponentUI UI)
+    {
+        super.setUI(new SteelCheckBoxUI(this));
+    }
+    // </editor-fold>
+
+    @Override
+    public String toString()
+    {
+        return "SteelCheckBox";
+    }
+}