0 -> species_0 0 -> species_1 species_0 -> 0 species_1 -> species_2 species_1 <-> species_3 0 -> species_4 species_5 -> 0 species_4 -> species_6 species_6 -> 0 0 -> species_7 0 -> species_8 species_9 -> 0 species_8 -> species_9 species_4 + species_8 <-> species_10 species_10 -> species_11 species_11 -> 0 species_10 <-> species_12 species_14 -> 0 species_2 -> 0 species_13 -> 0 0 -> species_5 species_12 -> species_14 species_7 -> 0 species_12 + species_3 <-> species_15 species_0 -> 0 species_5 -> 0 species_7 -> 0 species_8 -> 0 species_4 -> 0 species_9 -> 0 species_6 -> 0 species_11 -> 0 species_10 -> 0 species_14 -> 0 species_1 -> 0 species_2 -> 0 species_3 -> species_13 species_13 -> 0 species_15 -> 0 species_15 -> 0 species_3 -> 0 species_2 -> species_1 species_13 -> species_3 species_6 -> species_4 species_9 -> species_8 species_14 -> species_12 species_12 -> 0 species_11 -> species_10