function y=chafen(A)
 [m,n]=size(A);
 A1=ones(1,n);
 c=0;
 d=0;
 for i=1:1:n
     b=A(1,i);
     if c==b
         d=0;
     else d=1;
     end
     A1(1,i)=d;
     c=d;
 end
 y=A1;