Dim sd() As String = {"8:00","8:15","8:30","8:45"}
Dim sd1() As String = {"8:00","8:15"}
Dim sd1s As new List(of String)
sd1s.AddRange(sd1)
Dim cls As new List(of String)
For Each s As String In sd
If sd1s.Contains(s)=False Then
cls.Add(s)
End If
Next
For Each s As String In cls
output.show(s)
Next