Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest radiographs were obtained . The lungs are well expanded . Atelectasis at the left costophrenic angle is new . There is no focal consolidation , effusion , or pneumothorax . Cardiac and mediastinal contours are normal . There is no pneumoperitoneum . Thoracic degenerative changes are mild .
    OUTPUT:
    
1 . Left lower lobe atelectasis . 2 . No pneumoperitoneum .