    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
     
