code: protected int StackOpp()
  	{
  		if (key == "ifelse")
  			return -3;
  		if (key == "roll" || key == "put")
  			return -2;
  		if (key == "callsubr" || key == "callgsubr" || key == "add" || key == "sub" ||
  			key == "div" || key == "mul" || key == "drop" || key == "and" || 
  			key == "or" || key == "eq")
  			return -1;
  		if (key == "abs" || key == "neg" || key == "sqrt" || key == "exch" || 
  			key == "index" || key == "get" || key == "not" || key == "return")
  			return 0;
  		if (key == "random" || key == "dup")
  			return 1;
  		return 2;
  	}
docs: Function checks the key and return the change to the stack after the operator
  @return The change in the stack. 2-> flush the stack