I'm inferring that by "second pair of numbers" you mean "the second number in each pair of numbers".

while (<DATA>) # or wherever those lines come from
{
  chomp;
  my( $num, $str ) = split ' ', $_, 2;
  $str =~ s/^\d+,\s*//;
  $hash{$num} = $str;
}
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while (<DATA>) # or wherever those lines come from
{
  /^(\d+)\s+\d+,\s*(.*)/ and $hash{$1} = $2;
}
[download]