Help With Level Load

Hello, I am using unity5 1.2f1 In 2D and i am trying to make a level load script. The script says 'The name application' does not exist in the current context' and 'The name OnCollisionEnter' does not exist in the current context.' Can anyone help?

using UnityEngine; using System.Collections;

public class LevelLoad : MonoBehaviour {

 // Use this for initialization
 void Start () {


 }
 
 // Update is called once per frame
 void Update () {
     OnCollisionEnter ();
     {
         application.LoadLevel ("1");
     }
 
 }