Найти минимальный элемент ListBox - Visual Basic .NET

Public Class Form1
    Dim i, n, m, x, k As Integer
    Dim s, sr As Single
    Dim a(n) As String
    Dim b(n), max(n) As Integer
 
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        Dim i As Integer
        n = ListBox1.Items.Count
        ReDim a(n), b(n), max(n)
        For i = 0 To n - 1
            a(i) = ListBox1.Items(i)
            b(i) = ListBox2.Items(i)
        Next i
    End Sub
 
    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        ListBox1.Items.Add(TextBox1.Text)
 
    End Sub
 
    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
        ListBox2.Items.Add(TextBox2.Text)
    End Sub
    Private Sub Button2_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button2.Click
        Dim i As Integer
        x = b(0)
        For j = 1 To n - 1
            If b(j) > x Then x = b(j)
        Next
        k = 0
        For j = 0 To n - 1
            If b(j) = x Then
                max(k) = j
                k = k + 1
            End If
        Next
        For i = 0 To k - 1
            ListBox3.Items.Add(ListBox1.Items(max(i)))
            ListBox4.Items.Add(ListBox2.Items(max(i)))
        Next
    End Sub
 
    Private Sub Button4_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button4.Click
        Dim i As Integer
        s = 0 : sr = 0
        For i = 0 To n
            s = s + b(i)
        Next
        sr = s / n
        TextBox3.Text = sr
    End Sub
End Class