make surface shader in cg, unlit

I have a shader that makes a texture black and white, but the shader supports light. I would like to avoid using a light, and make it unlit. Here is my code:

Shader "Custom/blackAndWhiteShader" {
	 Properties {
        _Color ("Main Color", Color) = (1,1,1,1)
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _bwBlend ("Black & White blend", Range (0, 1)) = 0
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200
        #pragma surface surf Lambert
        sampler2D _MainTex;
        float4 _Color;
        float _bwBlend;
        struct Input {
            float2 uv_MainTex;
        void surf (Input IN, inout SurfaceOutput o) 
            half4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
            half lum = c.r*.3 + c.g*.59 + c.b*.11;
            half3 bw = half3( lum, lum, lum );
 			o.Normal = (.5,.5,.5);
            o.Albedo = lerp(c.rgb, bw, _bwBlend);
           // o.Emission = (1,1,1,.5);
            o.Alpha = c.a;
    Fallback "VertexLit"

How can i edit my code to make my shader unlit? I fear it may not work for surface shader and has something to do with Lambert (diffuse light).

You should just be able to do this:

   half4 LightingUnlit(SurfaceOutput s, half3 lightDir, half atten)
        return half4(s.Albedo, s.Alpha);

Then make your #pragma

    #pragma surface surf Unlit


Put this tag “Tags {“LightMode” = “Always”}”, but the tris count will go up a lot