Below is an instruction that describes a task. Write a response that appropriately completes the request in Thai. Please answer in Thai.

### Instruction:
Hally and her friends organized a high school reunion. To cover the cost of a late-night party that they planned for at the reunion, each attendee had to pay $100. After the party, Hally and her friends realized that the total expenses were $500 less than the total contributions. If there were 50 people at the party, how much money was used to pay for the party expenses?

### Response:
 ยอดเงินรวมที่ได้รับคือ $100 x 50 = $<<100*50=5000>>5000
ค่าใช้จ่ายรวมคือ $5000 - $500 = $<<5000-500=4500>>4500