466 seems to be impossible which is a shame cause i liked this game a lot and really wanted to finish it. 
you have to remove the red 1 cause otherwise purple goes down and you cant remove it and you loose. then you have to remove the red 2 for the same reason. if you dont remove red 3 obviously the green one will go there and then you are in the position when you have to remove three lilypads in one go for you to not lose.