Problem with BRDF Shader

Hi ! I wanted to make a BRDF shader but i ran into trouble .

Used tihs tutorial to make the shader : Youtube Tutorial Video

I wrote everything right in the shader but i get a error :

Program 'SurfShaderInternalFunc', expression left of . "Normal" is not a struct or array at line 30 .

And i can't understand what is causing this error .

Here is the shader :

 Shader "CTD/DemoBRDF" 
 {
 Properties 
 {
     _MainTex ("Base (RGB)", 2D) = "white" {}
     _Ramp2D ("BRDF Ramp", 2D) = "gray" {}
 }


 SubShader 
 {
     Tags { "RenderType"="Opaque" }
     LOD 200
     
     CGPROGRAM
     #pragma surface surf Ramp
     #pragma target 3.0

     sampler2D _MainTex;
     sampler2D _Ramp2D;

     struct Input 
     {
         float2 uv_MainTex;
     };

     half4 LightingRamp (SurfaceOutput s, half3 lightDir, half3 viewDir, half atten)
     {
            float NdotL = dot(s.Normal, lightDir);
            float NdotE = dot(s.Nornal, viewDir);

            //do diffuse wrap here
            float diff = (NdotL * 0.3) + 0.5;
            float2 brdfUV = float2(NdotE * .8, diff);
            float3 BRDF = tex2D(_Ramp2D, brdfUV.xy).rgb;

            float4 c;
            c.rgb = BRDF;//float3(diff,diff,diff);
            c.a = s.Alpha;
            return c;
      }

      void surf (Input IN, inout SurfaceOutput o) 
      {
          half4 c = float4(.5,.5,.5,1);//tex2D (_MainTex, IN.uv_MainTex);
          o.Albedo = c.rgb;
          o.Alpha = c.a;
      }
      ENDCG
  } 
  FallBack "Diffuse"
 }

If someone can help me then i would really apreciate him .

Thanks in advance for the upcoming answers :)