Errors CS1513 and CS1022 - Need help.

I'm just getting started with Unity and I don't know why I'm getting these errors:

Assets\PlayerMovementScript.cs(15,19): error CS1513: } expected Assets\PlayerMovementScript.cs(48,1): error CS1022: Type or namespace definition, or end-of-file expected

I've double-checked all the curly brackets and it doesn't seem wrong to me. Any clue of what could be happening here? I'm sorry if it's a dumb question, but I can't find what the problem is. Code:

 using System.Collections;
     using System.Collections.Generic;
     using UnityEngine;
     
     public class PlayerMovementScript : MonoBehaviour {
     
         public KeyCode upKey = KeyCode.W;
         public KeyCode downKey = KeyCode.S;
         public KeyCode rightKey = KeyCode.D;
         public KeyCode leftKey = KeyCode.A;
     
         public float speed = 4.0f;
         public Vector3 pos = player.transform.position;
         
         void Start() {    
     
             public GameObject player = GameObject.Find("Player");
         }
     
         void Update() {
     
             if (Input.GetKeyDown(upKey))
                {
                    pos.y += speed * Time.deltaTime;
     
             }
     
             if (Input.GetKeyDown(downKey))
                {
                    pos.y -= speed * Time.deltaTime;
     
             }
     
             if (Input.GetKeyDown(rightKey))
                {
                    pos.x += speed * Time.deltaTime;
     
             }
     
             if (Input.GetKeyDown(leftKey))
                {
                    pos.x -= speed * Time.deltaTime;
     
             }
     
             player.transform.position = pos;
         }
     }
 

Thanks in advance!