Classify each of the following accounts as either a real account (R) or a nominal account (N):
1. Cash
2. Sales Revenue
3. Accounts Receivable
4. Cost of Goods Sold
5. Prepaid Insurance
6. Capital Stock
7. Retained Earnings
8. Insurance Expense
9. Salaries Payable
10. Interest Expense
11. Insurance Premiums Payable
12. Salaries Expense
13. Accounts Payable
14. Prepaid Salaries
15. Utilities Expense
16. Notes Payable
17. Inventory
18. Property Tax Expense
19. Rent Expense
20. Interest Payable
21. Income Taxes Payable
22. Dividends
23. Buildings
24. Office Supplies
25. Income Tax Expense