char* timeConversion(char* str) {
    int h,m,s;
    sscanf(str, "%d:%d:%d", &h, &m, &s);
    if (h == 12) h = 0;
    if (str[8] == 'P') h += 12;
    
    static char out[9];
    sprintf(out, "%02d:%02d:%02d", h, m, s);
    return out;
}