"Encouraging progress." That's the feeling from mediators after the first round of talks between Iran and the US concluded in Switzerland. Those direct discussions were held to implement the memorandum of understanding. Their focus will now turn to using that agreement to negotiate a lasting peace deal within the next two months. Despite the positive atmosphere, there are hurdles to reaching a final agreement on that timeline. So, what would it take to overcome those challenges? And what concessions are the sides prepared to make to strike a deal?