0 -> M_P 0 -> M_T M_T -> 0 M_P -> 0 0 -> P0 0 -> T0 P0 -> 0 P1 -> 0 P2 -> 0 T0 -> 0 T1 -> 0 T2 -> 0 P2 + T2 -> C C -> 0 CN -> 0 C <-> CN P0 -> P1 P1 -> P2 P1 -> P0 P2 -> P1 T0 -> T1 T1 -> T2 T1 -> T0 T2 -> T1 T2 -> 0 P2 -> 0