ABC_ssa.bngl

begin seed species
  A 100
  B 100
end seed species
begin observables
  Molecules A A()
  Molecules B B()
  Molecules C C()
end observables
begin reaction rules
  A() + B() <-> C() 0.01, 1
end reaction rules

simulate({method=>"ssa",t_end=>10,n_steps=>500})