     0     1     0     0     0     0     1
     1     0     0     0     0     0     0     0
     0     1     1     0     0     0     1     0
     0     0     1     0     0     1     0     1
     0     0     0     1     0     0     1     0


ans = 

    'r'    's'    't'    'u'    'v'    'w'    'x'    'y'

</pre><img vspace="5" hspace="5" src="demo_01.png" alt=""> <p>This output means that vertex 'r' is row 1, vertex 's' is row 2 and because A(1,2) = 1, then there is an edge between them,
            just li