Miko_boc: Ivan I didn't mean A15 alone but B19B18A15 (maybe 'link position' function didn't work, sry).
It's still suboptimal though, I'd understand if you prefer not to accept such solutions.
d4rkm4tter: The problem is that after B19B18A15, opponent can play A18 to live. I added sequences.
omg my bad, thanks