open System

let read() = Console.ReadLine()

let N = read() |> ignore
let S = read().Split()
let T = read().Split()

(S,T)
||> Array.zip
|> Array.indexed
|> Array.find(fun x -> let l,r = snd x in l <> r)
|> (fun x ->
        let idx = (fst x) + 1
        let S   = (snd x) |> fst
        let T   = (snd x) |> snd
        printfn "%i" idx
        printfn "%s" S
        printfn "%s" T)