fragment shader different color for every vertex?

can i make different colors fore every instance of this shader? do i have to send instance to o.output or something? how can i do it?

                               StructuredBuffer<float3> buf_Points;
				StructuredBuffer<float3> buf_Positions;

				struct ps_input {
					float4 pos : SV_POSITION;
				};

				ps_input vert (uint id : SV_VertexID, uint inst : SV_InstanceID)
				{
					ps_input o;
					float3 worldPos = buf_Points[id] + buf_Positions[inst];
					o.pos = mul (UNITY_MATRIX_VP, float4(worldPos,1.0f));
					return o;
				}

				float4 frag (ps_input i) : COLOR
				{
					return float4(1,0.5f,0.0f,1);
				}

				ENDCG

solved it. its possible:"

		struct ps_input {
			float4 pos : SV_POSITION ;
			float4 col : COLOR;
		};

		ps_input vert (uint id : SV_VertexID, uint inst : SV_InstanceID)
		{
			bla

			
	
			o.pos = mul (UNITY_MATRIX_VP, float4(worldPos,1.0f));
			o.col = float4(sin(inst),0,0,1);
			return o;
		}

		float4 frag (ps_input i) : COLOR
		{
			return i.col;//float4(0.7f,.7f,.7f,1);
		}

		ENDCG