Correct answer: R:f31...g3 2.B:f3# 1.R:f3! (2.Rf2#/Rf4#/Rff5#/Rf6#/Rf7#/Rf8#/Re3#/Rd3#/Rc3#/Rfb3#/Rg3#/Rh3#) 1...Kc6 2.Rff
