Please help me solve this general accounting problem with the correct financial process.

At the beginning of the year, Greenwood Industries estimated manufacturing overhead for the year to be $315,600. At the end of the year, the actual direct labor hours worked were 26,500 hours, the actual manufacturing overhead incurred was $312,000, and the manufacturing overhead was over applied by $8,400. If the predetermined overhead rate is based on direct labor hours, what must have been the estimated direct labor hours at the beginning of the year