6 1 ((1.Human_Horai, 2.Human_Arnason) #1, (3.Chimp_Horai, 4.Chimp_Arnason) #1, (5.Gorilla_Horai, 6.Gorilla_Arnason) #1 ); // end of file. the reast of the file are notes. branch labels: 1: between species 0: within species