NullReferenceException: Object reference not set to an instance of an object

I want to add 1 point to script A from script B but an error pops up(refer to title).
I don’t know what’s wrong with it.

movto2tama is the name of the script B.

Script A:

public var pluspoints : movto2tama;

    function Update()

Script B:

private var points : int = 0;

function APoint()
	points = points + 1;


Likely ‘movtotama’ has not be assigned. You an drag the object that contains Script B onto the movto2tama variable in the inspector to do a link. Or you could setup the variable in Start(). Something like:

    movto2tama = GameObject.Find("NameOfGameObjectContainingScriptB");