#!/usr/bin/perl
use strict;
my $max;
while (<DATA>) {
  if (/rev(\d+)/) {
    if ($1 > $max){
      $max = $1;
    }
  }
}
print "max rev = $max\n";
__DATA__
    `-- added
    |-- add.txt
    `-- added1
        |--action
        |   |-- action.txt
        |   `-- rev1
        |   |    `-- rev9999.html
        |   `-- rev2
        |       `-- rev1.html

        `-- add.html