use strict;
use warnings;
use Data::Dumper;

my %HoA;

while (<DATA>)
  {
  chomp;
  next if ! length $_;
  my ($key, $time) = split ",";
  if (! $HoA{$key})
    {push @{$HoA{$key}}, $time;}
  elsif (@{$HoA{$key}} == 1)
    {push @{$HoA{$key}}, $time;}
  else
    {${@{$HoA{$key}}}[1] = $time;}
  }
  
print Dumper (%HoA);