Identifier Expected: Public is a keyword

What does this mean?

here is my code:

     using UnityEngine;
     using UnityEngine.UI;// we need this namespace in order to access UI elements within our script
     using System.Collections;
     using UnityEngine.Internal
     
 public class pause : MonoBehaviour 
     {
         public Canvas PauseMenu;
         public RawImage PauseScreen;
         
         void Start ()
             
         {
             PauseMenu = PauseMenu.GetComponent<Canvas>();
             PauseScreen = PauseScreen.GetComponent<RawImage> ();
             PauseMenu.enabled = false;
             
         }
         void Update (){
         if(Input.GetKeyDown("p")) {
 
             PauseMenu.enabled = true;
             FirstPersonController.enabled = false;
         }
         if (Input.GetKeyDown ("Esc")) {
             PauseMenu.enabled = false;
             FirstPersonController.enabled = true;
             
     }
     }
 }

I'm currently attempting a pause screen for my game, but it won't work.... why is this? Thanks!