Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest demonstrate stable top normal heart size . The mediastinal silhouette and hilar contours are normal . Linear opacities in the left lower lung zone are consistent with atelectasis . No pleural effusion or pneumothorax .
    OUTPUT:
    
Bibasilar atelectasis . No pneumonia