Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . Aside from mild lower lung atelectasis , the lungs appear clear . The heart and mediastinal contours are unchanged . No large effusion or pneumothorax is seen . No overt edema . Bony structures are intact .
    OUTPUT:
    
No definite signs of pneumonia . Mild basilar atelectasis .