use Math::BigFloat;

sub SqrRoot {
    my $num = Math::BigFloat->new( shift );
    my $iterations = shift || 50;
    my $guess = Math::BigFloat->new( $num / 2 );
    for ( 1..$iterations ) {
        $guess = (( $num / $guess ) + $guess ) / 2;
    }
    return $guess;
}