[![enter image description here][1]][1][![enter image description here][2]][2]


I'm trying to replace a basic on/off switch for the fan in my powder room with a timer switch (which requires a neutral). The timer switch comes with red, white, black and green wires.

In the same box there's also an existing light switch. 




  [1]: https://i.sstatic.net/Q7yeF.jpg
  [2]: https://i.sstatic.net/GLn82.jpg