let a = stdin.ReadLine ()
let b = stdin.ReadLine ()

let inta, intb =
    try
        int a, int b
    with
        | _ -> printfn "NG"; exit 0

if 0 <= inta && inta <= 12345 && 0 <= intb && intb <= 12345 && (a.Length = 1 || a.[0] <> '0') && (a.Length = 1 || b.[0] <> '0') then
    "OK"
else
    "NG"
|> printfn "%s"