After scene reload this Mathf.Round(Time.time * 3) stopped working.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class CharacterController2 : MonoBehaviour {
 
 public float speed;
 public float moveSpeed;
 private bool isDead = false;
 private Rigidbody2D rb2d;    
 void Start ()
 {
     
 }
 void Update (){
     if (isDead == false) {
         CheckUserInput ();
 
 
     }
 }
 void CheckUserInput () 
 {
     if (Input.GetKeyDown (KeyCode.A)) {
         transform.position += new Vector3 (-1, 0, 0);
     }
 
     if (Input.GetKeyDown (KeyCode.D)) {
         transform.position += new Vector3 (1, 0, 0);
     }
     if (Input.GetKeyDown (KeyCode.W)) {
         transform.position += new Vector3 (0, 1, 0);
     }
 
     if (Input.GetKeyDown (KeyCode.S)) {
         transform.position += new Vector3 (0, -1, 0);
     }
     if (Mathf.Round(Time.time * 3) - speed == moveSpeed) {
         transform.position += new Vector3 (0, 1, 0);
         speed = Mathf.Round(Time.time * 3);    ///////////AFTER scene reload time "stopped working"
     
 }
 }
 
 void OnCollisionEnter2D(Collision2D other)
 {        
     isDead = true;
     GameManager.instance.BirdDied ();
 }
 }

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine.SceneManagement;
 using UnityEngine;
 
 public class GameManager : MonoBehaviour {
 public static GameManager instance;    
 public bool gameOver = false;
 
 // Use this for initialization
 void Awake () {
 
     //If we don't currently have a game control...
     if (instance == null)
         //...set this one to be it...
         instance = this;
     //...otherwise...
     else if(instance != this)
         //...destroy this one because it is a duplicate.
         Destroy (gameObject);
     
 }
 
 // Update is called once per frame
 void Update () {
     //If the game is over and the player has pressed some input...
     if (gameOver && Input.GetMouseButtonDown (0)) {
         //...reload the current scene.
         SceneManager.LoadScene(SceneManager.GetActiveScene ().buildIndex); //////RELOAD
     }
 }
     public void BirdDied()
     {
         
         gameOver = true;
     }
 }