SQL & PL/SQL

I have some jobs scheduled.I am querying the table user_jobs there i am getting 50 rows.I want to remove the job.

i am executing the statement below through a sql statement:

exec dbms_job.remove(110) ;
exec dbms_job.remove(200);
.................
.................
..................
where 110,200 is the job[obtained from user_jobs].

The execution is taking long time. Does anybody has knowlegde how to remove oracle scheduled job?

Thanks in advance...