new empty 1 size 0 member 1 1 0 root0 insert 2 3 empty 0 size 1 member 1 1 0 member 2 3 1 min_x 2 min_y 3 max_x 2 max_y 3 sum_x 2 sum_y 3 insert 4 -2 member 4 -2 1 min_x 2 min_y -2 max_x 4 max_y 3 sum_x 6 sum_y 1 root x 2 y 3 ne0 nw0 sw0 se x 4 y -2 ne0 nw0 se0 sw0 exit insert 5 9 insert -7 11 min_x -7 min_y -2 max_x 5 max_y 11 size 4 insert 5 9 size 4 delete summary