RRB NTPC CBT I 18 Jan 2021 Shift 1 Paper

There are 21 persons and there are three languages - French German and Japanese. 10 persons speak German, 12 persons speak Japanese, and 10 persons speak French. 4 can speak only French and 5 can speak only Japanese. 4 can speak French as well as German. 3 persons can speak all languages. How many persons speak Japanese and German?