xyz -- The hardest number game

xyz is the hardest number game in the year of 2014. just swipe on the screen, the colorful cards will be merged once they have the same value.
It is very easy? NO !!!!, It is easy to get letter 'N' or 'R', but It is really hard to get the letter 'Z'.
What are you waiting for? Try to get letter 'Z' now !!!!!

Join the letters and get to the letter 'Z' !!!!!!