Web Forms :: Set Different Colors In Pie Chart

Am working in asp.net4.5 and facing problem piechart rendering.

Here is the code:

<div>
<asp:Chart ID="WebChart1" runat="server">
<%--<Series>
<asp:Series Name="Series1" ChartType="Pie"></asp:Series>
</Series>
<ChartAreas>
<asp:ChartArea Name="ChartArea1"></asp:ChartArea>

[Code] ....

when i run this am able to see two yello color and two green color and one red color datapoint in my piechart. how to i club the datapoint to show one green color, one yello color and one redcolor datapoint. because i should have only three colors with three area of plotting.