open System

[<EntryPoint>]
let main argv =
    let str = Console.ReadLine()
    let ss = str.Split [| ' ' |]
    let nums = Array.map int ss
    let prod = (nums.[0]) * (nums.[1])
    let sum = Array.sum nums
    let diff = (nums.[0]) - (nums.[1])
    let ans = List.max [prod; sum; diff]
    printfn "%i" ans
    0