def get_video_results(preds, anomaly_frames, normal_frames):
    """Returns confusion matrix values for predictions of one video
    Args:
        preds (set): set of frame number predictions for a threshold
        anomaly_frames (set) set of frames numbers that are anomalies
        normal_frames (set) set of normal frame numbers
    Returns:
        dict: true positives (int), false positives (int), false negatives (int), true negatives (int)
    """
    
    tp = 0
    fp = 0
    fn = 0
    tn = 0

    for pred_frame in preds:
        if pred_frame in anomaly_frames:
            tp += 1
        else:
            fp += 1     
    
    for frame_number in anomaly_frames:
        if frame_number not in preds:
            fn += 1
            
    for frame_number in normal_frames:
        if frame_number not in preds:
            tn += 1
            
    return {"tp": tp, "fp": fp, "fn": fn, "tn": tn}