$m{$_} = ++$i for qw[Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec];
($a, $t, $f, $b) = qw[([A-Za-z]+) \b(\d\d)\b (\d{4}) (\d{4}|\d\d)];

for (<>) {
    ($y, $m, $d) =
        /$f-$t-$t/   ? ($1, $2, $3) :
        /$t\/$t\/$t/ ? ($3, $1, $2) :
        /$t#$t#$t/   ? ($2, $1, $3) :
        /$t\*$t\*$f/ ? ($3, $2, $1) :
        /$a $t, $b/  ? ($3, $m{$1}, $2) : next;
    $y += $y < 50 ? 2000 : $y < 100 ? 1900 : 0;
    printf "%04d-%02d-%02d\n", $y, $m, $d;
}