#!/usr/bin/env perl

use strict;
use warnings;

use List::Util qw(reduce max all);

# Functional

# Imperative
my @primes = (2);
sub factorize {
    my $n = shift;
    for my $i ($primes[-1] .. $n) {
        push @primes, $i if all { $i % $_ != 0 } @primes;
    }
    my $factors;
    for my $prime (@primes) {
        if ($n % $prime == 0) {
            $factors->{$prime}++;
            $n /= $prime;
            redo;
        }
    }
    return $factors;
}

sub merge_factors {
    my $fst = shift;
    my $snd = shift;
    my $res;
    foreach my $k (keys %$fst) {
        $res->{$k} = max($res->{$k} || 0, $fst->{$k});
    }
    foreach my $k (keys %$snd) {
        $res->{$k} = max($res->{$k} || 0, $snd->{$k});
    }
    return $res;
}

my @factors = map { factorize $_ } (2..20);
my $mcm = reduce { merge_factors($a, $b) } @factors;

my $res = 1;
foreach my $k (keys %$mcm) {
    $res *= $k ** $mcm->{$k};
}
print $res, "\n";