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;
}

It's funny how people want efficiency, so they use C, sometimes they want to embed a language, but then they realize making a full compiler would be too much work for them, so they end up making an interpreter, which would mean overall slower code execution (the only time when interpreters beat compilers is when the expressions are short and easy to interpret, as well as situations when your interpreted code calls EVAL internally for everything it does - which is not a good programming practice (lol FEXPRS)). Instead they could choose something more high-level, but on average slightly slower than C (unless more work is done to optimize things), which allows code transformation, and gives you direct runtime access to a compiler. Such a language could be Common Lisp, but it's not the only one(however it's one of the few languages which support real macros).