小王设计了一个程序来列举仁川亚运会的奖牌前三的国家。下列VB程序实现如下功能：单击命令按钮Command1后，在列表框List1中按奖牌数由多到少显示国家名称，如图。

请根据算法将下列程序补充完整。

Dim a(1 To 45) As String

Dim b(1 To 45) As Integer

Private Sub Form_Load()

  a(1) = "中国"

  b(1) = 308

 ‘45个代表团名称及奖牌数分别放在a(1)到a(45)及b(1)到b(45)中

End Sub

Private Sub Command1_Click()

Dim i As Integer,j As Integer

Dim t As Integer,f As Integer

List1.Clear

 For i = 1 To 3

   For j = To 2 Step -1

    If Then

     f = a(j): a(j) = a(j - 1): a(j - 1) = f

     t = b(j): b(j) = b(j - 1): b(j - 1) = t  

   End If

   Next j

 Next i

For i = 1 To 3

 List1.AddItem "第" + Str(i) + "名" + a(i) + "  奖牌数" + Str(b(i))

Next i

End Sub