Perl sort descending by 2nd column and print/write the first line

Hey guys,

I have a file (PFA) and I will need to do in perl the following:

for each 'YYYY-MM-DD HH NN' to sort descending by second column then print/write just the first (highest) value like: YYYY-MM-DD HH:00 NN. Please bear in mind while sorting, I want that the first column to be taken without minutes (MM). Should be a king of group by YYYY-MM-DD HH then get the highest value of second column. I need this for different day/hour/etc. The columns are tab separated, like YYYY-MM-DD HH:MM \t NN.

 As example, the results of below lines should be:

2009-03-04 15:00      34

2009-03-04 15:28      30
2009-03-04 15:29      30
2009-03-04 15:30      28
2009-03-04 15:31      30
2009-03-04 15:32      30
2009-03-04 15:33      31
2009-03-04 15:34      32
2009-03-04 15:35      31
2009-03-04 15:36      34
2009-03-04 15:37      34
2009-03-04 15:38      32
2009-03-04 15:39      31
2009-03-04 15:40      30
2009-03-04 15:41      29
2009-03-04 15:42      28


I hope everything is clear. If not, please let me know. Thanks a lot in advance.

Cheers,
Dan.
mylog.txt