Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette size is normal . The mediastinal and hilar contours are unremarkable . Pulmonary vascularity is normal . The lungs are clear . No pleural effusion or pneumothorax is noted . There are mild degenerative changes in the left acromioclavicular joint .
    OUTPUT:
    
No acute cardiopulmonary abnormality .