Random Grid Genaration with walls C#

Hi everyone, sorry for my bad english. I have a problem making borders of my grid with this script i can create a grid

 using UnityEngine;
 using System.Collections;
 
 public class array : MonoBehaviour {
     public GameObject Tile_Walk;
     public GameObject Tile_Wall;
     public GameObject PG;
     public int GridX;
     public int GridY;
     // Use this for initialization
     public int PGX;
     public int PGY;
     int i;
     int j;
     void Start() {
         PGX = Random.Range(1, (GridX - 1));
         PGY = Random.Range(1, (GridY - 1));
         for (i = 0; i < GridX; i++)
         {
                 for (j = 0; j < GridY; j++)
                 {
                     if ((j!=0) &&(i!=0)&& (j != GridY) && (i != GridX)) {
                     
                         
                                 Instantiate(Tile_Walk, new Vector3(i, j, 0), Quaternion.identity);
                          
                     }
                     else 
                     
                     Instantiate(Tile_Wall, new Vector3(i, j, 0), Quaternion.identity);
 
                 }
             }
             Instantiate(PG, new Vector3(PGX, PGY, -1), Quaternion.identity);
         }
 
         // Update is called once per frame
         void Update () {
 
         }
     } 
 

but it look like this...

how can i make Walls in all borders?

edit:prblem solved

 using UnityEngine;
 using System.Collections;
 
 public class array : MonoBehaviour {
     public GameObject Tile_Walk;
     public GameObject Tile_Wall;
     public GameObject PG;
     public int GridX;
     public int GridY;
     // Use this for initialization
     public int PGX;
     public int PGY;
     int i;
     int j;
     void Start() {
         PGX = Random.Range(1, (GridX - 1));
         PGY = Random.Range(1, (GridY - 1));
         for (i = 0; i < GridX; i++)
         {
                 for (j = 0; j < GridY; j++)
                 {
                     if ((j!=0) &&(i!=0)&& (j != GridY-1) && (i != GridX-1)) {
                     
                         
                                 Instantiate(Tile_Walk, new Vector3(i, j, 0), Quaternion.identity);
                          
                     }
                     else 
                     
                     Instantiate(Tile_Wall, new Vector3(i, j, 0), Quaternion.identity);
 
                 }
             }
             Instantiate(PG, new Vector3(PGX, PGY, -1), Quaternion.identity);
         }
 
         // Update is called once per frame
         void Update () {
 
         }
     }