A couple wishes to retire in Santa Rosa Beach, Florida. The couple will need to withdraw $12,319.00 per month (beginning of the month) in retirement to live in a nice condo near the ocean. Their money will earn 3.48% APR with monthly compounding in retirement. They expect retirement to last 30.00 years. The couple would also like to leave $509,090.00 to charity at the end of their retirement. They will retire in 20.00 years. Currently, they have $97,452.00 in savings and invest in a mutual fund each month that pays a 7.92% APR (monthly compounding) on average. What monthly investment will allow them to reach their goal? (assume end of month contributions)