shanten calculation problem

[Preserver6166]

bad cases:
145s36m12579p256z result=6, expected=5
12479s5p344569m5z result=4, expected=3

Actually about 20% cases are not correct，you can test it on
https://tenhou.net/2/?q=12479s5p344569m5z

[bonarc712]

Thank you for flagging this, I will look into it when I will have a bit more time.