Correct answer: f4+1...Kf4+ 2.Ng:e6# 1...Kd6+ 2.R:e6# 1...Rf4 2.Nf5# 1.Nd3+?? 1...Kd4+ 2.N:e6# 1...Kd6+ 2.R:e6# but 1...Kf6+! 1.Nd7+?
