Brace Corporation uses direct labor-hours in its predetermined overhead rate. At the beginning of the year, the estimated direct labor-hours were 21,600 hours. At the end of the year, actual direct labor-hours for the year were 20,400 hours, the actual manufacturing overhead for the year was $506,920, and manufacturing overhead for the year was underapplied by $23,440. The estimated manufacturing overhead at the beginning of the year used in the predetermined overhead rate must have been?