A person opens a savings account at a bank that earns 5% interest, compounded annually. Four years after depositing a principal sum into the account, the account contains exactly $5,000. Assuming a 5% annual interest rate is appropriate, the implied annual interest is $5,000 0.05 = $250, and the present value of the savings is $5,000 0.82270 = $4,114. How much principal did the person deposit?