use strict;
use warnings;

my $data = "Exlief 4    page : 1 /10";
my $match = qr/pag\w+\s*:\s*(\d+)[^\d]*(\d+)/;

print "Pages : $1 / $2\n" if $data =~ $match;

$data = "Exlief 4    page : 1 / 5";

print "Pages : $1 / $2\n" if $data =~ $match;