Speed Slide Puzzle

Please input the sentence that you want to translate here. The input language is judged automatically. I move a number with an empty trout and am a classic puzzle game to sort at the position same as completion form. Because it becomes a thyme attack system, please sort it as soon as possible. With 15 puzzles which there are 15 pieces on a board of 4x4 There are 8 puzzles which there are 15 pieces on a board of 3x3. I am called the sliding block puzzle.