Mahjong Required Tiles

A puzzle app using mahjong tiles.
Find the required mahjong tiles to win with flush.
In Practice mode, you can see the answer of each question.
In Time Attack mode, you will get the following points for each question.

Points:
with Full Flush
Not Tenpai…..10pt
Number of required tiles is less than 3…..10pt/tile
3-4…..15pt/tile
more than 4…..20pt/tile

with Half Flush
Not Tenpai…..5pt
Number of required tiles is less than 3…..5pt/tile
3-4…..10pt/tile
more than 4…..15pt/tile

Wrong Answer…..-10pt