--- /dev/null
+#!/usr/bin/perl -w
+
+use strict;
+
+my @nums = sort { $a <=> $b } <>;
+chomp @nums;
+
+my %is_listed = map { $_ => 1 } @nums;
+
+for my $i (0 .. $#nums-1) {
+ for my $j ($i .. $#nums) {
+ my $rest = 2020-$nums[$i]-$nums[$j];
+ if ($rest > 0 && $is_listed{$rest} && $rest != $nums[$i]
+ && $rest != $nums[$j]) {
+ print "$nums[$i]*$nums[$j]*$rest=", $nums[$i]*$nums[$j]*$rest, "\n";
+ last;
+ }
+ }
+}
+