Keybinding for adding a paper to a shared folder?

Right now if I wish to add a paper to a shared folder, I need to drag the grey 3x2 rectangle to the shared folder. Is there a keybinding available so that I don’t need to use the mouse? Something similar to “l” for adding a label would be a great. (I see “f” is there, and adds it to a folder, but not a shared folder.)