有如下Visual Basic程序：

Private Sub Command1_Click()

Dim i As Integer, c As Integer, n As Integer

n = Val(Text1.Text)

c = 0

For i = 1 To n

If i Mod 3 = 0 Then c = c + 1

Next i

Label1.Caption = Str(c)

End Sub

运行该程序，在文本框Text1中输入20，单击命令按钮Command1，在标签Label1中显示的是。