S1 = sparse(6,6);
S2 = sparse(6,6);
S1(1,2)=0.1;
S1(1,4)=0.8;
S1(1,5)=0.1;
S2(1,1)=0.4;
S2(1,2)=0.6;
S1(2,3)=0.5;
S1(2,5)=0.5;
S2(2,3)=1;
S1(3,3)=1;
S1(4,4)=1;
S1(5,4)=0.6;
S1(5,5)=0.4;
S2(5,6)=1;
S1(6,3)=0.9;
S1(6,6)=0.1;
S2(6,5)=1;