def s( d ) :
    ''' Solves the sigma.s() homework 24 problem description
    '''

    pass




''' DO NOT MODIFY THE BELOW CODE ''''
    
if ( __name__ == '__main__' ) :
    import sigma

    d1 = [ [ 0 ],             [ 1, 2 ],             [ 1, 2, 3 ], [ 0 ]       ]
    d2 = [ [ 1, 0, 1, 2, 2 ], [ 3, 0, 1, 1, 1, 0 ], [ 2 ],       [ 0, 0, 1 ] ]
    d3 = [ [ 3, 0, 3],        [ 3, 0, 3, 0, 1],     [ 1, 0, 2 ]              ]
    d4 = [ ]


    s1 = sigma.s( d1 );       print( 's( d1 ) =', s1 )
    s2 = sigma.s( d2 );       print( 's( d2 ) =', s2 )
    s3 = sigma.s( d3 );       print( 's( d3 ) =', s3 )
    s4 = sigma.s( d4 );       print( 's( d4 ) =', s4 )