Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . There is mild left basal atelectasis . No convincing evidence for pneumonia . No congestion or edema . No large effusion or pneumothorax . The cardiomediastinal silhouette is normal . Imaged osseous structures are intact . Partially imaged right humeral head prosthesis noted . No free air below the right hemidiaphragm is seen .
    OUTPUT:
    
Mild left basal atelectasis , otherwise unremarkable .