my $num_zeros = 3; my $num_ones = 2;
use Math::BigInt;
sub fac {
    my $result = Math::BigInt->new("1");
    my $n = Math::BigInt->new(shift());
    while($n){ $result *= $n--; }
    return $result;
}
my $num_permutations = fac($num_ones + $num_zeros ) / (fac($num_ones) * fac($num_zeros));
print("Number of permutations of a ($num_zeros, $num_ones) list is $num_permutations\n");'