Sipple Furniture's master budget for the year includes $339,600 for fixed supervisory salaries. Practical capacity, which is used to set the fixed overhead allocation rate, is 630 units per month. Supervisory salaries are expected to be incurred uniformly throughout the year. During August, the company produced 380 units, incurred production supervisory salaries of $29,650, and reported underapplied fixed overhead of $20,500 for supervisory salaries. What is Sipple Furniture's supervisory salaries spending (budget) variance for August? Is this variance favorable (F) or unfavorable (U)? (Leave no cell blank; if there is no effect enter "0" and select "None" from dropdown.)