The ornamental design for a cutter, as shown and described.
1. Cutter
The design application shows a new cutter; fig. 1.1 is a perspective view; fig. 1.2 is a front view; fig. 1.3 is a perspective view of the cutter folded; fig. 1.4 is a bottom view; fig. 1.5 is a top view; fig. 1.6 is a right view; and fig. 1.7 is a left view.