To do it the easy way, just keep asking the book repeatedly until it says "Break the wall" and puts another book on the wall.

There are three idols that you have to ask for questions. For 1st one on left (Blue top): Use Eclia. For middle one (Red top): Lelie. For last one on right (Yellow top): Ciel. If it doesn't work, then it means that the program is randomizing it and you'll have to brute force it!