My program accepted. This is correct output:

sihT si na elpmaxe fo a elpmis tset. fI uoy did ton nu-dnatsred eht gnirehpic mhtirogla tey,
neht etirw eht srettel fo hcae drow ni eht esrever redro. yB eht yaw, "gnisrever" eht txet
eciwt serotser eht lanigiro txet.

In sample the word "un-derstand" write incorrect!!!