Simple audio script glitch

Hello,

I made this script i’ll explain what it does when you press down wsad it plays the audio file of grass walking when i release it stopped well it works only for the w key on release the asd keeping looping the audio file is there something i’m doing wrong?

using UnityEngine;
using System.Collections;

public class PlayerAudio : MonoBehaviour {
	
	public AudioSource Audio;
	public AudioClip WalkingOnGrass;

	// Update is called once per frame
	void Update () {
		if(Input.GetKeyDown("w") || Input.GetKeyDown("s") || Input.GetKeyDown("a") || Input.GetKeyDown("d"))
			audio.Play();
		else if 
		(Input.GetKeyUp("w") || Input.GetKeyDown("s") || Input.GetKeyDown("a") || Input.GetKeyDown("d"))
			audio.Stop(); 
	}

}

if(Input.GetKeyDown(“w”) || Input.GetKeyDown(“s”) || Input.GetKeyDown(“a”) || Input.GetKeyDown(“d”))
audio.Play();
else if

         (Input.GetKeyUp("w") || Input.GetKeyDown("s") || Input.GetKeyDown("a") || Input.GetKeyDown("d"))
             audio.Stop(); 
     }

You need Input.GetKeyUp ‘SAD’ lol