species_0 + species_1 <-> species_2
species_1 + species_3 <-> species_5
species_1 + species_4 <-> species_9
species_5 <-> species_6 + species_7
species_6 <-> species_1 + species_8
species_3 + species_9 <-> species_10
species_4 + species_5 <-> species_10
species_0 + species_5 <-> species_11
species_0 + species_6 <-> species_12
species_4 + species_6 <-> species_13
species_10 <-> species_13 + species_7
species_13 <-> species_8 + species_9
species_2 + species_3 <-> species_11
species_11 <-> species_12 + species_7
species_12 <-> species_2 + species_8
species_0 + species_9 <-> species_14
species_2 + species_4 <-> species_14
species_14 + species_3 <-> species_15
species_11 + species_4 <-> species_15
species_0 + species_10 <-> species_15
species_15 <-> species_16 + species_7
species_0 + species_13 <-> species_16
species_12 + species_4 <-> species_16
species_16 <-> species_14 + species_8