Private Sub MaskedTextBox1_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles MaskedTextBox1.LostFocus
        If IsNumeric(MaskedTextBox1.Text.Split("M")(1)) Then
            Dim k As String = MaskedTextBox1.Text.Split("M")(1)
            Dim numof0 As Integer = 4
            For i As Integer = 0 To numof0 - MaskedTextBox1.Text.Split("M")(1).Length
                k = "0" & k
            Next
            MaskedTextBox1.Text = k
        End If
    End Sub