$5r^{8}\left(-2r^{2}\left(s^{6}-t^{11}\right)+5\right)\left(s^{6}-t^{11}\right)^{4}$

$10r^{10}t^{55}-50s^{6}r^{10}t^{44}+100r^{10}s^{12}t^{33}+25r^{8}t^{44}-100r^{10}s^{18}t^{22}-100s^{6}r^{8}t^{33}+50r^{10}t^{11}s^{24}+150r^{8}s^{12}t^{22}-10r^{10}s^{30}-100r^{8}t^{11}s^{18}+25r^{8}s^{24}$