Merge 2 shaders

I have 2 shaders: one that keys a green background and one the applies a mask.

I would like to combine them into one shader but am having trouble (I don't have much experience with writing shader scripts)

Everything I've tried has resulted in errors.

Can anyone help me merge these please?

Chroma Key Shader:

 Shader "UniversalChromaKey" {
         Properties {
                 _MainTex ("Base (RGB)", 2D) = "white" {}
                 _Sens ("Sensibilidad", Range (0,.9)) = .3
                 _Cutoff ("Recorte", Range (0,.9)) = .2
                 _Color ("Chroma", Color) = (0, 1.0, 0)
         }
         SubShader {
                 Tags { "Queue"="Transparent" "RenderType"="Transparent" }
                 LOD 200
                
                
                 CGPROGRAM
                 #pragma surface surf Lambert alpha:blend
  
                 sampler2D _MainTex;
                 float _Cutoff;
                 float _Sens;
                 half3 _Color;
 
  
                 struct Input {
                         float2 uv_MainTex;
                 };
  
                 void surf (Input IN, inout SurfaceOutput o) {
                         half4 c = tex2D (_MainTex, IN.uv_MainTex);
                         o.Albedo = c.rgb;
                         
                         
                         float aR = abs(c.r - _Color.r) < _Sens ? abs(c.r - _Color.r) : 1;
                         float aG = abs(c.g - _Color.g) < _Sens ? abs(c.g - _Color.g) : 1;
                         float aB = abs(c.b - _Color.b) < _Sens ? abs(c.b - _Color.b) : 1;                        
                         
                         float a = (aR + aG + aB) / 3; 
                         
                         if(a < _Cutoff){
                             o.Alpha = 0;
                         }else{
                             o.Alpha = 1;
                         }
                           
                 }
                 ENDCG
         }
         FallBack "Diffuse"
 }

Masking Shader:

 Shader "MaskingShader"
 {
     Properties
     {
         [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
         _Alpha ("Alpha", Range(0,1)) = 1
         _MaskTex ("Masking Texture", 2D) = "white"{}
     }
  
     SubShader
     {
         Tags
         {
             "Queue"="Transparent-1"
             "IgnoreProjector"="True"
             "RenderType"="Transparent"
             "PreviewType"="Plane"
             "CanUseSpriteAtlas"="True"
         }
  
         Cull Off
         Lighting Off
         ColorMask RGBA
         ZWrite Off
         Blend One OneMinusSrcAlpha
  
         Stencil
         {
             Ref 1
             Comp always
             Pass replace
         }
  
         Pass
         {
         CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
             #pragma multi_compile _ PIXELSNAP_ON
             #include "UnityCG.cginc"
  
             struct appdata_t
             {
                 float4 vertex   : POSITION;
                 float4 color    : COLOR;
                 float2 texcoord : TEXCOORD0;
             };
  
             struct v2f
             {
                 float4 vertex   : SV_POSITION;
                 fixed4 color    : COLOR;
                 half2 texcoord  : TEXCOORD0;
             };
  
             v2f vert(appdata_t IN)
             {
                 v2f OUT;
                 OUT.vertex = UnityObjectToClipPos(IN.vertex);
                 OUT.color = IN.color;
                 OUT.texcoord = IN.texcoord;
  
                 return OUT;
             }
  
             sampler2D _MainTex;
             sampler2D _MaskTex;
             Float _Alpha;
  
             fixed4 frag(v2f IN) : SV_Target
             {
                 fixed4 original = tex2D(_MainTex, IN.texcoord);
                 fixed4 masked = tex2D(_MaskTex, IN.texcoord);
                 return fixed4(original.r * masked.a * _Alpha, original.g * masked.a * _Alpha,original.b * masked.a * _Alpha, masked.a * _Alpha);
             }
         ENDCG
         }
     }
 }