Validate Password

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Bai2
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                string temp = Console.ReadLine();
                if (temp == "-1") break;
                if (validatePassword(temp)) Console.WriteLine("Yes");
                else Console.WriteLine("No");
            }
        }

        static bool checkSymbol(char input)
        {
            string symbol = "!@#$%^&*()";
            foreach (char value in symbol)
            {
                if (value == input) return true;
            }
            return false;
        }
        static bool validatePassword(string n)
        {
            bool haveNumber = false, haveUpper = false, haveLower = false, haveSymbol = false;
            if (n.Length < 8) return false;

            foreach(char value in n)
            {
                if (char.IsNumber(value)) haveNumber = true;
                if (char.IsLower(value)) haveUpper = true;
                if (char.IsUpper(value)) haveLower = true;
                if (checkSymbol(value)) haveSymbol = true;
            }
            if (haveNumber == true && haveUpper == true && haveLower == true && haveSymbol == true) return true;
            return false;
        }
    }
}