#!/usr/bin/perl
# your code goes here
use Data::Dumper;
my %session_called = ();
for my $sid (qw/1 2 3 1 1 1 3 4 5 2/) {
$sesion_called{$sid} ++;
}
print Dumper
(\%sesion_called) . "\n";
my @duped = grep { $session_called{$_} > 1 } keys %session_called;
print Dumper
(\@duped) . "\n";
IyEvdXNyL2Jpbi9wZXJsCiMgeW91ciBjb2RlIGdvZXMgaGVyZQoKdXNlIERhdGE6OkR1bXBlcjsKCm15ICVzZXNzaW9uX2NhbGxlZCA9ICgpOwoKZm9yIG15ICRzaWQgKHF3LzEgMiAzIDEgMSAxIDMgNCA1IDIvKSB7Cgkkc2VzaW9uX2NhbGxlZHskc2lkfSArKzsKfQpwcmludCBEdW1wZXIoXCVzZXNpb25fY2FsbGVkKSAuICJcbiI7CnByaW50IGpvaW4oJywnIGtleXMgJXNlc3Npb25fY2FsbGVkKSAuICJcbiI7CgpteSBAZHVwZWQgPSBncmVwIHsgJHNlc3Npb25fY2FsbGVkeyRffSA+IDEgfSBrZXlzICVzZXNzaW9uX2NhbGxlZDsKCnByaW50IER1bXBlcihcQGR1cGVkKSAuICJcbiI7Cg==