x1 = EmptySet
x2 = CCc
x3 = CCn
x4 = Clkc
x5 = Clkm
x6 = Perc
x7 = Perm
x8 = PTc
x9 = PTn
x10 = Timc
x11 = Timm
x12 = species_0000012
x13 = species_0000013