#!/usr/bin/perl
use strict;
my $probability = permutation(50, 5);
print $probability * 36;

sub permutation
{
    my $number = shift;
    my $count = shift || return 1;
    return $number * permutation($number-1,$count-1);
}

##</code><code>##

sub permutation
{
     return $_[1] ? $_[0] * permutation($_[0]-1,$_[1]-1) : 1;
}