Tutorial for rougelike is telling me code is wrong

Ive tried everything I can think of to fix this code. Eventually I just copied and pasted the code from tutorial website and it was identical to the one I wrote. Its still wrong. Here is what I have so far.

using UnityEngine;
using System.Collections;

namespace Completed
{
	using System.Collections.Generic;       //Allows us to use Lists. 
	
	public class GameManager : MonoBehaviour
	{
		
		public static GameManager instance = null;              //Static instance of GameManager which allows it to be accessed by any other script.
		private BoardManager boardScript;                       //Store a reference to our BoardManager which will set up the level.
		private int level = 3;                                  //Current level number, expressed in game as "Day 1".
		
		//Awake is always called before any Start functions
		void Awake()
		{
			//Check if instance already exists
			if (instance == null)
				
				//if not, set instance to this
				instance = this;
			
			//If instance already exists and it's not this:
			else if (instance != this)
				
				//Then destroy this. This enforces our singleton pattern, meaning there can only ever be one instance of a GameManager.
				Destroy(gameObject);    
			
			//Sets this to not be destroyed when reloading scene
			DontDestroyOnLoad(gameObject);
			
			//Get a component reference to the attached BoardManager script
			boardScript = GetComponent<BoardManager>();
			
			//Call the InitGame function to initialize the first level 
			InitGame();
		}
		
		//Initializes the game for each level.
		void InitGame()
		{
			//Call the SetupScene function of the BoardManager script, pass it current level number.
			boardScript.SetupScene(level);
			
		}
		
		
		
		//Update is called every frame.
		void Update()
		{
			
		}
}

its saying that I need another bracket on the last line but adding one messes up the level generation.

put the using System.Collections.Generic; Line above namespace Completed