Besides performing a procedure ie ERCP (as above), there are other less invasive imaging modalities that can be useful in visualising the biliary system. One of it being CT cholangiogram, where the contrast dye is given and CT scan was performed at specific timing to capture images as shown on the radiopaedia link https://radiopaedia.org/cases/normal-ct-intravenous-cholangiogram?lang=us. Based on the image below, how many gallstones can you visualise in the gallbladder?