Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral radiographs of the chest demonstrate clear lungs . Mild left atrial enlargement is noted . Otherwise the hilar and cardiomediastinal contours are normal . There is no pneumothorax or pleural effusion . Pulmonary vascularity is normal .
    OUTPUT:
    
1 . No evidence of pneumonia or pulmonary edema . 2 . Mild left atrial enlargement .