        let hantei a b = if (a + b) mod 3 = 0 then "Possible"
        else if a mod 3 = 0 then "Possible"
        else if b mod 3 = 0 then "Possible"
        else "Impossible"
         
        let main () =
        let kekka = hantei A B
        print_string kekka;
         
        let = main ()