use strict;
use warnings;

my @myarray;
while(<>)
{
 chop;
 my($id, $data) = $_ =~ /(\d+)\s(.*)/;
 push (@{$myarray[$id]}, "$data");
}
 
for(my $i=0;$i<@myarray;$i++)
{
 next unless defined($myarray[$i]);
 foreach my $data ( @{$myarray[$i]} )
 {
  print "$i $data\n";
 }
}