There is a disclosure of a system which controls a folding unit performing folding processing to one set of sheets supplied by a print unit. The one set of sheets includes sheets of a first size and/or a second size which is smaller than the first size. The system includes a first controller and second controller. When the one set of sheets includes a sheet of the first size, the first controller inhibits the folding processing to a sheet of the second size. When the one set of sheets does not include a sheet of the first size but includes a sheet of the second size, the second controller permits the folding processing to a sheet of the second size.