1. An input method comprising: an operation-input display step of displaying information related to an operation input at a display position; a detecting step of detecting a touch of an object at a touch position on a first surface behind the information displayed at the operation input display step; a touch-position display step of displaying a mark at a mark position directly above the touch position, the mark representing the touch position; and an input step of determining whether the display position of the information displayed at the operation-input display step and the mark position of the mark displayed at the touch-position display step are overlapped, and when overlapping is determined, executing an input process corresponding to the overlapped information.