Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest demonstrate the lungs are well expanded and clear . A trace amount of linear atelectasis is present at the left lung base . No focal opacity concerning for pneumonia is identified . Aortic knob calcifications are again seen . The cardiomediastinal silhouette is unremarkable . No pulmonary edema or pleural effusion . No pneumothorax is identified .
    OUTPUT:
    
No acute cardiopulmonary process .