FE*RNN
FE*NNN
F*RNN
FE*ERN
FE*RRN
FE*RN*
FF*ERN
FF*RNN
FR*NNN
FR*RNN
F*FRN
F*RRN
*FER
FF*NNN
F*NNN
FF*FRN
FF*RRN
FR*RRN