Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are normal . The lung shows normal structure and transparency . With the exception of a small atelectasis at the left lung bases the lung parenchyma is free of parenchymal opacities . No lung nodules or masses . Normal size of the cardiac silhouette . Normal appearance of the hilar and mediastinal structures on both the frontal and the lateral image .
    OUTPUT:
    
No evidence of lung nodules or masses .