12 10 +-+------+-+ | | | | | +--- +-+ | | | | | -+ --+- -| | | | | | -++- --| |-+ | ---+ |SD | | +-----+----+ 5 3 +---+ |S D| +---+ 9 10 +---+---+ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |D| |S| +-+---+-+ 5 5 +---+ |S | +---+ | D| +---+ 12 10 +-+------+-+ | D | | | | | | | | | | | | | |S | +-----+----+ 7 4 +-----+ | | |S|-|D| +-----+ 40 15 +--------------------------------------+ | | | | | | | | | | | | | | | | | | | | | | | | | SD | +--------------------------------------+