Juega a Sushi Mahjong

What to eat today? I feel like eating sushi! Coming to a lovely sushi restaurant and trying to eat delicious sushi needs to get through. Combine 2 of the same mahjong stones to remove them from the playing field. You only can use free stones. A free stone is not covered by another stone and at least one side, left or right, is open. How many levels can you clear?