Detect Long Press and single tap to make higher jumps

hi, i'm currently making a 2D endless runner, when the player taps on the screen once the object should jump a certain height say x, if the player long presses on the screen the object should jump again with a height say y (where y > x). this the code that i'm using , but it does'nt work for me.

         Player.velocity = new Vector2 (PlayerVelx * Time.deltaTime,Player.velocity.y);
 
         isGrounded = Physics2D.IsTouchingLayers (PlayerCollider,Ground);
 
 
         if (Input.touchCount > 0) 
 
         {
 
         if (Input.GetTouch(0).phase == TouchPhase.Began) 
 
             { 
                 if (isGrounded) 
                 {
                     Press.text = "Short Jump "; 
                     Player.velocity = new Vector2 (Player.velocity.x, PlayerVely * Time.deltaTime);
                 }
             }
 
         if (Input.GetTouch(0).phase == TouchPhase.Stationary ) 
 
             { 
                 if (isGrounded) 
                 {
                     Press.text = "Long Jump "; 
                     Player.velocity = new Vector2 (Player.velocity.x, PlayerVelyLong * Time.deltaTime);
                 }
             }
 
 
         }

Any help would be appreciated. thanks!