let read() = stdin.ReadLine().Split() |> Array.map int64 
let N,K = let t = read() in t.[0],t.[1]
let D   = read()
 
D
|> Array.zip [|1L..N|]
|> Array.filter (fun tup -> fst tup <> snd tup)
|> Array.length
|> fun x -> max (x-1) 0 
|> int64
|> function | x when x<=K && (K-x)%2L=0L -> "YES" | _ -> "NO"
|> printfn "%s"