Guys what is wrong with the position of node

This is the two pieces of faulty code, public Vector3 Position; and Position = a_Pos; .unexpected symbol position and public in class struct or interface member declaration

this is the full code:

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class Node {

 public int gridX; 
 public int gridY; 

 public bool IsObstacle 
 public Vector3 Position; 

 public Node Parent; 

 public int gCost; 
 public int hCost;

 public int FCost {get{return gCost + hCost;}} 

 public Node (bool a_IsObstacle, Vector3 a_Pos, int a_gridX, int a_gridY)

 {
     IsObstacle = a_IsObstacle 
     Position = a_Pos;  
     gridX = a_gridX;
     gridY = a_gridY; 
 }

}

Help :"(