at least one first memory storing program instructions; and

at least one first processor configured to execute the instructions stored in the first memory to:

acquire a capturing time of a lesion image instructed to be saved by a user, from a series of images captured by an endoscope during examination of a large intestine with the endoscope;

acquire a capturing time of a lesion image detected by detection processing for the series of images captured by the endoscope during the examination;

acquire a first lesion image that is the lesion image instructed to be saved by the user,

acquire a second lesion image that is the lesion image detected by the detection processing;

specify, from the series of images, an image in which an ileocecal valve, or an entrance portion of an appendix is captured, the ileocecal valve, or the entrance portion of the appendix being a site corresponding to a start position of the examination;

cause a display device to display a first capturing time and a second capturing time which are plotted on a time axis, the first capturing time being the capturing time of the lesion image instructed to be saved by the user, the second capturing time being the capturing time of the lesion image detected by the detection processing;

perform control so as to display the first lesion image in association with the first capturing time, and display the second lesion image in association with the second capturing time;

perform control so as to plot the second capturing time after a capturing time of the image in which the ileocecal valve, or the entrance portion of the appendix is captured, on the time axis; and

based on an instruction to select the first lesion image or the second lesion image input from the user and detection failure information of the selected lesion image input from the user, generate feedback data in which the lesion image and the detection failure information are associated with each other, the feedback data being data for improving detection accuracy of the detection processing, wherein

the detection failure information includes information indicating the lesion image depicted with a lesion detected by the user although the detection is overlooked by the detection processing.