If your parents aren't related, nor their parents, the 30th-generation(roughly 600–900 years depending on generation length) ancestor group size is 2^30, which is about 1.07 billion.
https://www.youtube.com/watch?v=HclD2E_3rhI
"only 72% of these 7th great grandparents will give you some of your genetics"
"over less than 400 years, 97% of your ancestors contribute nothing to your genetics"