# define binary relationships
tree ((((Scer,Spar),Smik),Skud),Sbay);

# define labels on the internal nodes of the tree 
define A as Scer,Spar
define B as Scer,Smik
define C as Scer,Skud
define R as Scer,Sbay

# define a hybridization event
hybridization Sbay R, Skud C as H D tau=yes,no phi=0.4