app.config console

Hello I'm trying to use app.config in a simple console application, but my code isn't working. Can please someone check my code?

app.config

<configuration>
  <appSettings>
    <add key="level" value="5"></add>
  </appSettings>
</configuration>

console1

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

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            string level = System.Configuration.ConfigurationManager.AppSettings["level"];
            Console.WriteLine("Logger level: " + level);
            Console.ReadLine();
        }
    }
}