module Yuki

open System

let solve a b =
    let rec isA ax bx =
        match ax, bx with
        | 7L :: _, 4L :: _ ->
            false
        | 4L :: _, 7L :: _ ->
            true
        | a :: ax, b :: bx ->
            if a > b then true
            elif a < b then false
            else isA ax bx
        | ax, [] -> failwith ""
        | [], bx -> failwith ""
        
    let a' = string a
    let b' = string b
    if a'.Length > b'.Length then
        a
    elif a'.Length < b'.Length then
        b
    else
        let a'' = a'.ToCharArray() |> Array.map (string>>int64) |> Array.toList
        let b'' = b'.ToCharArray() |> Array.map (string>>int64) |> Array.toList
        if isA a'' b'' then
            a
        else
            b
    

let A, B = 
    let t = 
        Console.ReadLine().Split() 
        |> Array.map int64
    t.[0], t.[1]

solve A B
|> Console.WriteLine