FinancialManagement
TimeLimit:1000MS Memory Limit:10000K
TotalSubmissions:157065 Accepted:60269
Description
Larry graduated this year and finally has ajob.
Larry今年畢業了，並且找到了工作。
He's making a lot of money, but somehownever seems to have enough.
他賺了很多錢，但不知怎的總覺得不夠。
Larry has decided that he needs to grabhold of his financial portfolio and solve his financing problems.
他決定，他需要把握住他的投資組合（這句感覺好彆扭，有沒有更好的翻譯，求指點），以解決他的經濟問題。
The first step is to figure out what's beengoing on with his money.
首先要算出他的錢都去哪了
Larry has his bank account statements andwants to see how much money he has.
Larry得到了他的銀行賬單，想要查看他有多少錢。
Help Larry by writing a program to take hisclosing balance from each of the past twelve months and calculate his averageaccount balance.
幫助Larry寫一個程序，計算他過去12個月的終期餘額和他的平均賬戶餘額
Input
The input will be twelve lines. Each linewill contain the closing balance of his bank account for a particular month.
輸入包含12行，每一行是他一個月的終期餘額。
Each number will be positive and displayedto the penny. No dollar sign will be included.
輸入的每個數都是一個正數，顯示到分。沒有美元符號。
Output
The output will be a single number, theaverage (mean) of the closing balances for the twelve months.
輸出只有一個數，表示12月的平均餘額。
Itwill be rounded to the nearest penny, preceded immediately by a dollar sign,and followed by the end-of-line.
精確到分，開頭加上美元符號，最後接一個行尾結束符
（注end-of-line意思是行尾結束符，一般來說就是\n）
There will be no other spaces or charactersin the output.
輸出不包含空格或其他符號
Sample Input
100.00
489.12
12454.12
1234.10
823.05
109.20
5.27
1542.25
839.18
83.99
1295.01
1.75
Sample Output
$1581.42