Mandy plans to attend community college for 2 years before transferring to a university. The annual cost of the community college she will attend is $6,400. She has $2,500 in her savings that she can use. She also has a one-time grant worth $2,000. Assuming the cost of tuition stays the same, how much more money does Mandy need to pay for 2 years of tuition at community college?