You are planning to save for retirement over the next 15 years. To do this, you will invest $1,000 a month in a stock account and $600 a month in a bond account. The return of the stock account is expected to be 7 percent, and the bond account will pay 4 percent. When you retire, you will combine your money into an account with an 6 percent return. Assuming a 20-year withdrawal period, you can withdraw $______________ each month from your account.