Using variables from UnityScript in Boo?

Hello, I've been trying to implement this but without any success. While I was googling around I saw that this is somehow possible but I can't reach it by myself obviously. This my file tree:

 |-Game
 |--Assets
 |---Animacije
 |---Skripte
 |----*BlokSistem.js
 |---Standard Assets
 |----*UI.boo
 |---Prefabs
 |---Sprites
 |---Game.unity

I want to use variable from BlokSistem.js in UI.boo, but without any success. I want to change one and print another. Here is my code for now:

 import UnityEngine
 import System.Collections
 
 public class UI(MonoBehaviour):
        
        blokSistem as BlokSistem = GetComponent[of BlokSistem]() #this is line 7 which produces error
     
        def OnGUI() as void:
            GUI.Box(Rect(0,0,200,50), "Blocks")
            if GUI.Button(Rect(0,60,200,25), "Dirt = "+blokSistem.dirtAmount):
                   blokSistem.selectedBlock = blokSistem.dirtBlock
            elif GUI.Button(Rect(0,60,200,25), "Grass = "+blokSistem.grassAmount):
                 blokSistem.selectedBlock = blokSistem.grassBlock

I get this error on line 7 (commented it in code above):

 The name 'BlokSistem' does not denote a valid type ('not found'). 

This is how I declared my variables in BlokSistem.js:

 public var dirtAmount : int;
 public var grassAmount : int;
 public var selectedBlock : GameObject;

Thanks in advance for help.