Teach me to remove bloat!

Hey guys, I would like some pointer (no, not that kind) on removing bloat in code. Here is a fully functional piece of code that I wrote which I'm worried about bloat in. How do I shorten this?

int get_input()
{
    int count, paren_count, total_count, c;
    char *input, *temp;

    input = (char *) malloc (500 * sizeof (char));

    if (input == NULL) return 0;
    printf("%% ");
    for (count = paren_count = total_count = 0; (c = getchar()) != EOF; count++, input++, total_count++)
    {
        if (count == 499)
        {
            input -= total_count;
            temp = (char *) realloc (input, (500 + total_count) * sizeof (char));
            if (temp == NULL)
                return 0;
            input = temp;
            input += total_count;
        }
        if (c == '\n')
        {
            *input = '\0';
            temp = input;
            temp -= (count);
            count = 0;
            for (; *temp != '\0'; temp++)
            {
                if (*temp == '(')
                    paren_count++;
                else if (*temp == ')')
                    paren_count--;
            }
            if (paren_count == 0)
                break;
            printf("  ");
        }
        *input = c;
    }
    *temp = '\0';
    input -= total_count;
    printf("%s\n", input);
    free(input);
    return 0;
}

Common Lisp is a really bad choice if you're looking for ways to reduce bloat. It will eat up 30-60MB RAM depending on the implementation. And that's just the Lisp environment itself without any of your own code.
Unless you're using something like CLISP (~8MB), but it's slow.

>>76
I'm just trying to say that current Common Lisp implementations are doing it wrong. Lisp machines are dead. They should stop trying to act like one.