Task: Question Generation
Input (English): Context : F 13 Norrköping, Bråvalla Flygflottilj, Bråvalla Air Force Wing, or simply ``F 13'', is a former Flygvapnet - Swedish Air Force - wing with the main base located near Norrköping in south-eastern Sweden. 
Answer : Swedish Air Force
Output (English): What military branch did F 13 Norrköping belong to?