Financial Management

Larry graduated this year and finally has a job. He is making a lot of money, but somehow never seems to have enough. Larry has decided to take control of his financial portfolio and solve his money problems. The first step is to figure out where his money has been going. Larry has his bank account statements and wants to know how much money he has on average. Given the closing balance of his bank account for each of the past twelve months, write a program that computes his average (mean) account balance.

The input consists of twelve lines. Each line contains the closing balance of the bank account for one month. Every amount is positive and given to the penny (two decimal places). No dollar sign is included.

Print the average balance on a single line: a dollar sign ($) immediately followed by the mean of the twelve closing balances rounded to the nearest penny (an exact half penny rounds up), then a newline. Print no other spaces or characters.