List Countries

{
  "type": "object",
  "description": "Countries List",
  "required": [
    "countries",
    "sum"
  ],
  "properties": {
    "countries": {
      "type": "array",
      "description": "List of countries.",
      "items": {
        "type": "object",
        "description": "Country",
        "required": [
          "name",
          "code"
        ],
        "properties": {
          "code": {
            "type": "string",
            "description": "Country two-character ISO 3166-1 alpha code."
          },
          "name": {
            "type": "string",
            "description": "Country name."
          }
        }
      }
    },
    "sum": {
      "type": "integer",
      "format": "int32",
      "description": "Total sum of items in the list."
    }
  }
}