Multi layer texture transparent when not supposed to

Hi, I am kinda new when it comes to shaders, so I am trying to make a few things in order to learn.

One the things i am trying to do is a flage made of four textures in differents layers, each layer with its own color. The thing is, it is almost ok, but th parts that i need not being transparent are a little see through

here's my shader:

 Shader "Custom/CustomLayers"
 {
     Properties
     {
         _FirstTex("Texture", 2D) = "white" {}
         _FirstColor("Color", Color) = (1,1,1,1)
         _SecondTex("Texture", 2D) = "white" {}
         _SecondColor("Color", Color) = (1,1,1,1)
         _ThirdTex("Texture", 2D) = "white" {}
         _ThirdColor("Color", Color) = (1,1,1,1)
         _FourthTex("Texture", 2D) = "white" {}
         _FourthColor("Color", Color) = (1,1,1,1)
     }
         SubShader
         {
             Tags { "Queue" = "Transparent" "RenderType" = "Transparent" }
             LOD 200
 
         CGPROGRAM
         // Physically based Standard lighting model, and enable shadows on all light types
         #pragma surface surf Standard fullforwardshadows alpha
 
         // Use shader model 3.0 target, to get nicer looking lighting
         #pragma target 3.0
 
         sampler2D _FirstTex;
         sampler2D _SecondTex;
         sampler2D _ThirdTex;
         sampler2D _FourthTex;
 
         struct Input
         {
             float2 uv_FirstTex;
             float2 uv_SecondTex;
             float2 uv_ThirdTex;
             float2 uv_FourthTex;
         };
 
         fixed4 _FirstColor;
         fixed4 _SecondColor;
         fixed4 _ThirdColor;
         fixed4 _FourthColor;
 
         UNITY_INSTANCING_BUFFER_START(Props)
             // put more per-instance properties here
         UNITY_INSTANCING_BUFFER_END(Props)
 
 
         void surf (Input IN, inout SurfaceOutputStandard o)
         {
             // Albedo comes from a texture tinted by color
             fixed4 c0 = tex2D(_FirstTex, IN.uv_FirstTex) * _FirstColor;
             fixed4 c1 = tex2D(_SecondTex, IN.uv_SecondTex) * _SecondColor;
             fixed4 c2 = tex2D(_ThirdTex, IN.uv_ThirdTex) * _ThirdColor;
             fixed4 c3 = tex2D(_FourthTex, IN.uv_FourthTex) * _FourthColor;
 
             fixed4 tt = c0 + c1 + c2 + c3;
 
             tt.rgb = lerp(c0.rgb, c1.rgb, c1.a);
             tt.rgb = lerp(tt.rgb, c2.rgb, c2.a);
             tt.rgb = lerp(tt.rgb, c3.rgb, c3.a);
 
             o.Albedo = tt.rgb;
             o.Alpha = tt.a;
         }
         ENDCG
     }
     FallBack "Diffuse"
 }
 

Anyone can light my candle?