Shader error syntax error help

 Shader "Custom/snow" {
     Properties {
         _MainTex("Base (RGB)", 2D) = "white" {}
         //New normal map texture
         _Bump("Bump", 2D) = "bump" {}
     }
     SubShader {
         Tags { "RenderType"="Opaque" }
         LOD 200
         
         CGPROGRAM
         // Physically based Standard lighting model, and enable shadows on all light types
         #pragma surface surf Lambert
 
         // Use shader model 3.0 target, to get nicer looking lighting
         #pragma target 3.0
 
         sampler2D _MainTex;
 
         //Must add a sample with the same name
         sampler2D _Bump;
 
         struct Input {
             float2 uv_MainTex;
             float2 uv_Bump;
         };
 
         void surf (Input IN, inout SurfaceOutput o) {
             half4 c = tex2D(_MainTex, IN.uv_MainTex);
 
             //Extract the normal map information from the texture
             o.Normal = UnpackNormal(tex2D(_Bump, IN.uv_Bump);
 
             o.Albedo = c.rgb;
             o.Alpha = c.a;
         }
         ENDCG
     }
     FallBack "Diffuse"
 }
 

On the line, o.Normal = UnpackNormal(tex2D(_Bump, IN.uv_Bump); there is a syntax error although I can't seem to find anything wrong with it.