Assets/World/scripts/World.cs( 5,1 ): error CS1041: Identifier expected: public is a keyword

here’s my code

using UnityEngine;
using System.Collections;
using System.Collections.Generic

public class World : MonoBehaviour {

private int size;
private byte[,,]content;

//0 nada
//1 bloco

protected Mesh mesh;
protected List<Vector3> vertices = new List<Vector3>();
protected List<int> triangles = new List<int>();

// Use this for initialization
void Start () {
	content = new byte[size,size,size];
	for (int x=0; x<size; x++) {
		for (int z=0; z<size; z++) {
			content [x,0,z] = 1;
		}
	}

	mesh = new Mesh ();
	GetComponent<MeshFilter> ().mesh = mesh;

}

// Update is called once per frame
void Update () {

}

}

@7hm123 The error message indicates line 5 is in error. There is a semi-colon missing at end of using statement before the public keyword:

using System.Collections.Generic;