Instruct: Classify the given review into positive or negative sentiment.
Query: Rough, but worth it

21 grams, directed by Mexican director Alejandro Gonzalex Inarritu takes us through the stories of three characters, played by Sean Penn, Naomi Watts, and Benicio Del Toro, in an un-chronological way. Penn plays a dying man in need of a heart transplant whose wife desperately wants a child before he goes. Watts plays a wife and mom trying to get past her drug addiction and return to a stable life. Del Toro's story is the most interesting of the three as an ex-con who begins to straighten up his life convinced that Jesus has given him another chance at it. These three characters all come colliding together in interesting ways, and it is truly a movie that makes you think. There are some very rough edges of the film, with rough scenes to go along with it, but the film's intention and terrific acting make it one that I want to see again.