You are given a raw data file (INPUT.DAT) containing three numbers per line, separated by commas. Some sample Lines are as follows: Notice that one of the lines only contains two numbers. Read this...

You are given a raw data file (INPUT.DAT) containing three numbers per line, separated by commas. Some sample Lines are as follows:

Notice that one of the lines only contains two numbers. Read this data file, using a DATA _NULL_ DATA step, and create another raw data file (OUTPUT.DAT) containing the same data as INPUT.DAT except that values of 9999 are replaced by a SAS missing value. The output file should look like this: