Need help with entering information for "Sold Principal Residence" I put in the information for line 18 as the year "2000" the year the home was bought.

Apparently I need to put in data in line 181 that gives the date of acquisition of my home.  This is the year "2000" which is a 4 digit number.  Information I get is this " an entry on line 179 of 1 or 2 (I used 1)  however, then entry on line 181 is other than 4 digits.  So what do I enter on line 181?