%Graph Adjacency Matrix A
%     1 2 3 4 5 6 7 8 9 1011121314151617181920
A = [ 0 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0 0 0 ; %1
      0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 ;
      1 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 ;
      0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 1 0 0 ;
      0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 ; %5
      0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 ;
      1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 ;
      0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 ;
      0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 ;
      0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 ;%10
      0 0 0 0 0 0 0 0 1 1 0 0 0 0 1 0 0 0 0 0 ;
      0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 1 0 ;
      0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 ;
      0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ;
      0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ; %15
      0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ;
      0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 ;
      0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ;
      0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ;
      0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 ]; %20