transition:    
s1-a-s2;
s2-c-s1;
s1-a-s3;
s3-b-s4;
s4-a-s5;
s5-b-s4;
s4-a-s6;
s6-c-s7;
s7-c-s6;
s7-a-s8;
s8-b-s9;
s9-a-s10;
s8-b-s9;
initial:
s1;
final:
s1;
s2;
s5;
s6;
s10.