开门时超过20个硬币

我尝试着让玩家在收集到20个硬币时打开unity的一扇门。当你碰它的时候它就会打开。但出于某种原因。当我用0、1、2等硬币碰它时，它仍然会打开。我该如何预防呢?

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class Player_Controller : MonoBehaviour {
public float speed;
public Text countText;
private Rigidbody rb;
private int count;
public float volume;
public Text eye;

AudioSource audio;
void Start()
{
    audio = GetComponent<AudioSource>();
    rb = GetComponent<Rigidbody>();
    count = 0;
    SetCountText();
    eye.text = "";
}

void FixedUpdate()
{
    float moveHorizonal = Input.GetAxis("Horizontal");
    float moveVertical = Input.GetAxis("Vertical");
    Vector3 movement = new Vector3(moveHorizonal, 0.0f, moveVertical);
    rb.AddForce(movement * speed);
}
void OnTriggerEnter(Collider other)
{
    if (other.gameObject.CompareTag("pickup"))
    {
        audio.Play(); //Play it
        other.gameObject.SetActive(false);
        count = count + 1;
        SetCountText();
    }
    else if (other.gameObject.CompareTag("pickup2"))
    {
        audio.Play(); //Play it
        other.gameObject.SetActive(false);
        count = count + 10;
        SetCountText();
    }
    else if (other.gameObject.CompareTag("eye"))
    {
        audio.Play(); //Play it
        other.gameObject.SetActive(false);
        count = count + 9999999;
        SetCountText();
    }
    else if (other.gameObject.CompareTag("door") && count <= 20)
    {
        other.gameObject.SetActive(false);
        count = 0;
    }

}
void SetCountText()
{
    countText.text = "Count: " + count.ToString();
    if (count >= 9001)
    {
        eye.text = "You hit the bull's eye! ALL THE POINTS!";
    }
}
}

更新:我在这里使用了错误的字符。& lt;应该是>。但现在的问题是，因为这是一个触发器，你可以直接滚过去。我怎样才能让它既坚固又能触发?

else if (other.gameObject.CompareTag("door") && count <= 20)

else if (other.gameObject.CompareTag("door") && count >= 20)