How to remove JSON schema dynamically without hardcode in the output from API gateway response

Question

I know this is similar to this one but I am trying to remove JSON schema dynamically without using their data-types/key-params hardcoded in the loop.

This is the response from Integration response having dynamodb schema JSON structure.

{
  Items: [
    {
      {key1: {S: "Value1_1"}, key2:{S: "Value2_1"}, key3:{S: "Value3_1"}},
      {key1: {S: "Value1_2"}, key2:{S: "Value2_2"}, key3:{S: "Value3_2"}},
      {key1: {S: "Value1_3"}, key2:{S: "Value2_3"}, key3:{S: "Value3_3"}}
    }
  ]
}

I need to get this response from the above

{
  Items: [
    {key1: "Value1_1", key2: "Value2_1",key3: "Value3_1"},
    {key1: "Value1_2", key2: "Value2_2",key3: "Value3_2"},
    {key1: "Value1_3", key2: "Value2_3",key3: "Value3_3"},
  ]
}

Here is my code which I am trying to get that valid JSON.

#set($inputRoot = $input.path('$'))
{
  "Items": [
#foreach($elem in $inputRoot.Items)
    #foreach($paramName in $elem.keySet())
        #foreach($paramType in $paramName.keySet())
          {
            "$paramName" : "$util.escapeJavaScript($paramName.get($paramType))"
          }
          #if($foreach.hasNext),#end
        #end
      #if($foreach.hasNext),#end
    #end
  #if($foreach.hasNext),#end
#end
  ]
}

Can someone help me here to achieve the valid JSON format