#define PREVIOUS_FRAME(x) (*(int *)(x + ((int *)__builtin_frame_address(1) - (int *)__builtin_frame_address(0))))
void f(int x)
{
    if (x > 0)
    {
        x = -x;
        printf("1\n");
        f(-2);
    }
    else
    {
        if (PREVIOUS_FRAME(&x) <= x)
        {
            printf("%i\n", -x);
            if (PREVIOUS_FRAME(&x) != x)
                f(PREVIOUS_FRAME(&x));
        }
        else
        {
            printf("%i\n", -(PREVIOUS_FRAME(&x) - 1));
            if (x != PREVIOUS_FRAME(&x) - 1)
                f(PREVIOUS_FRAME(&x) - 2);
        }
    }
}