Input five Numbers find out Highest & Second Highest Number in VB.NET.

DESCRIPTION:
Highest Number Prime Or not & up to Second Highest Number  calculate Fibonacci series
PROPERTIES:

Label1
Text	(Empty)
Label2
Text	(Empty)
Button1
Text	Enter Number in Box

CODEING:

Public Class Form1
    Dim i As Integer = 1
    Dim k As Integer = 1
    Dim f_high, s_high As Integer
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        If i <= 5 Then
            If NumericUpDown1.Value > f_high Then
                s_high = f_high
                f_high = NumericUpDown1.Value
            ElseIf NumericUpDown1.Value > s_high And Not NumericUpDown1.Value = f_high Then
                s_high = NumericUpDown1.Value
            End If
            i += 1
            Button1.Text = "Enter " & i & " Number"
        End If
        If i = 6 Then
            Label1.Text = "Fibonacci series Up To " & s_high
            i = 0
            While i <= s_high
                If k <= s_high Then
                    Label2.Text = Label2.Text & " " & i & " " & k
                Else
                    Label2.Text = Label2.Text & " " & i
                End If
                i = i + k
                k = i + k
            End While
            i = 2
            k = 0
            While i <= f_high / 2 And  k = 0
                If f_high Mod i = 0 Then
                    k = 1
               else
                   i = i + 1
                End If
            End While
            If k = 0 Then
                MsgBox(f_high & " is Prime Number")
            Else
                MsgBox(f_high & " is not Prime Number")
            End If
        End If
    End Sub
End Class

DESIGNING: