using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Find("Nick"));

        Console.WriteLine(Find("Jack"));

        Console.WriteLine(Find("Mary"));

    }

    static int Find(string name)

    {

        var userList = new List<Dictionary<string, dynamic>>

        {

            new Dictionary<string, dynamic>

            {

                { "id", 1 },

                { "name", "Jack" }

            },

            new Dictionary<string, dynamic>

            {

                { "id", 2 },

                { "name", "Mary" }

            }

        };

​

        foreach (var user in userList)

        {

            if (user["name"] == name)

            {

                return user["id"];

            }

        }

        return -1;

    }

}