UPDATE 1-CBS plays to strength, adds 4 new shows for fall

* Adds one comedy, three dramas for fall

* Picks up "Medium" after NBC canceled the crime drama

* Moves "The Mentalist" to Thursday nights (Adds comments from CEO Moonves)

By Paul Thomasch

NEW YORK, May 20 (Reuters) - CBS unveiled on Wednesday a new comedy and three dramas, including one starring LL Cool J, making slight adjustments to the only prime-time television schedule to increase its audiences in the past season.

The shows joining CBS' prime-time schedule this fall follow the network's pattern of serving up stable but popular fare: a legal drama, a medical drama, a crime drama and an ensemble comedy.

"Nobody likes hearing they're not sexy," CBS Corp (CBS.N) Chief Executive Les Moonves told advertisers as he introduced the new schedule. "But the good news is we really like being No. 1."

To some degree, CBS faces less pressure than other TV broadcasters to announce radical schedule changes at the upfront, a period each spring when the networks set new prime-time lineups and advertisers pay billions of dollars for commercial time.

It was the only broadcast network to increase ratings during the 2008-09 season, and is home to "CSI," the top drama, "Two And A Half Men," the top comedy, and the long-running reality series "Survivor."