#!/usr/bin/env perl use strict; use warnings; my $n = <>; chomp $n; my %h; $h{1} = 1; for (my $i = 2; $i < 50; $i++) { $h{$i} = ($h{$i - 1} * $i) % 1000000000000; } if ($n >= 50) { print "000000000000\n"; } else { if ($n >= 15 && length $h{$n - 1} > length $h{$n}) { printf "%012d\n", $h{$n}; } else { printf "$h{$n}\n"; } }