Tree-span: [('p18', 'p21'), ('p45', 'p47'), ('p45', 'p49'), ('p45', 'p50'), ('p13', 'p20'), ('p13', 'p30'), ('p13', 'p31'), ('p13', 'p32'), ('p10', 'p16'), ('p10', 'p17'), ('p2', 'p14'), ('p2', 'p15'), ('p61', 'p63'), ('p61', 'p64'), ('p61', 'p65'), ('p61', 'p67'), ('p21', 'p22'), ('p21', 'p23'), ('p21', 'p24'), ('p21', 'p25'), ('p21', 'p26'), ('p21', 'p27'), ('p21', 'p28'), ('p21', 'p29')]
Graph-bridge: [('p46', 'p45'), ('p48', 'p45'), ('p62', 'p61'), ('p45', 'p47'), ('p45', 'p49'), ('p45', 'p50'), ('p66', 'p61'), ('p33', 'p13'), ('p68', 'p61'), ('p69', 'p61'), ('p13', 'p30'), ('p13', 'p31'), ('p13', 'p32'), ('p10', 'p16'), ('p10', 'p17'), ('p16', 'p2'), ('p2', 'p14'), ('p2', 'p15'), ('p61', 'p63'), ('p61', 'p64'), ('p61', 'p65'), ('p61', 'p67')]