let max x y =
    let add = x + y
    let sub = x - y
    let mul = x * y
    if add <= sub && mul <= sub then sub
    else if sub <= add && mul <= add then add
    else mul

stdin.ReadLine().Split(' ')
|> Array.map (int)
|> (fun xs -> (xs.[0], xs.[1]))
||> max
|> printfn "%d"