Pietro sold investment real estate for $85,000. His adjusted basis at the time was $80,000. He reported the gain using the installment method, with a gross profit percentage of 5.882%. Pietro repossessed the property when the buyer stopped making payments. Using the general rule for qualified real property, Pietro's taxable gain on repossession is $3,318. The unpaid balance of the installment obligation on the date of repossession is $70,000. Pietro incurred $800 in legal expenses to repossess the property.

What is Pietro's basis of the repossessed real property?