`UnityEngine.Camera.main' cannot be accessed with an instance reference, qualify it with a type name instead

New to C#, it's pedantic. I'm used to Matlab. Basically `UnityEngine.Camera.main' cannot be accessed with an instance reference, qualify it with a type name instead. In other words, it makes too much sense to be able to access the main camera by saying camera.main. How do I fix this?

using UnityEngine; using System.Collections;

public class Building : MonoBehaviour { public GameObject sphere1=null;

 // Use this for initialization
 void Start () {
     sphere1=Instantiate(Resources.Load("Prefabs/prefab_sphere")) as GameObject;
 }

 // Update is called once per frame
 void Update () {
     var playerObject = GameObject.Find("Player");
     var playerPos  = (Vector3)playerObject.transform.position;
         
     // var cam  = camera.GetComponent(main);

     var buildingPos = playerPos + camera.main.WorldToScreenPoint(Vector3.zero);
 
     Debug.Log(playerPos);
     if(Input.GetMouseButtonDown(0))
         sphere1=Instantiate(Resources.Load("Prefabs/prefab_sphere"),buildingPos,Quaternion.identity) as GameObject;
          

 }

}