{1,4,6,7}\{1,4,6,7\}{1,4,6,7}
{1,3,6,7}\{1,3,6,7\}{1,3,6,7}
{2,4,6,7}\{2,4,6,7\}{2,4,6,7}
{1,3,4,6}\{1,3,4,6\}{1,3,4,6}