I found a video with a tip in the internet I use it and this is my result, you should try it I think it is so usefull, to reduce the render time :D. This is the video https://www.youtube.com/watch?v=oSZ3C5OTU2E
That render have 100 samples :O.
In this kinid of scene you should get better results by increasing the radius of the denoiser (start very high like 32 and work your way down)