a[1] = tmp;
    if (!pplus && !pmult) {
        a[1] = concat(a[0], tmp);
        pconcat = operatorsrequired(v, a+1, n-1, 3);
        a[1] = tmp;
    }
    if (pconcat) return 3;
    if (pmult) return 2;
    if (pplus) return 2;
    if (pmult) return pmult;
    if (pplus) return pplus;
    return 0;
}

void aoc202407(char *data, size_t len) {
    (void)len; // unused argument
    unsigned long long calibrationtotal = 0, calibration3total = 0;
    char *line = strtok(data, "\n");