Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest demonstrate an opacity in the left upper lobe . The right lung is clear . The cardiomediastinal and hilar contours are stable . There is no pleural effusion or pneumothorax . A lesion in the anterior third rib has been slowly sclerosing since ___ and is almost certainly benign .
    OUTPUT:
    
Left upper lobe pneumonia .