如何在LINQ Where子句中搜索集合的集合？

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        List<List<int>> nestedList = new List<List<int>>
        {
            new List<int> { 1, 2, 3 },
            new List<int> { 4, 5, 6 },
            new List<int> { 7, 8, 9 }
        };

        int target = 5;
        var result = SearchNestedList(nestedList, target);

        Console.WriteLine($"The target {target} is found in the nested list: {result}");
    }

    static bool SearchNestedList(List<List<int>> nestedList, int target)
    {
        foreach (var list in nestedList)
        {
            if (list.Contains(target))
            {
                return true;
            }
        }

        return false;
    }
}

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        List<List<int>> nestedList = new List<List<int>>
        {
            new List<int> { 1, 2, 3 },
            new List<int> { 4, 5, 6 },
            new List<int> { 7, 8, 9 }
        };

        int target = 5;
        var result = nestedList.SelectMany(x => x).Where(x => x == target).Any();

        Console.WriteLine($"The target {target} is found in the nested list: {result}");
    }
}