如何计算一个JObject中有多少个字段是用LINQ设置的？

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    public static void Main()
    {
        string json = "{\"field1\": \"value1\", \"field2\": \"value2\", \"field3\": \"value3\"}";

        JObject jObject = JObject.Parse(json);
        Dictionary<string, JToken> dictionary = jObject.ToObject<Dictionary<string, JToken>>();

        int count = dictionary.Where(kv => kv.Value is JValue).Count();

        Console.WriteLine("The number of fields set using LINQ in the JObject is: " + count);
    }
}