open System
let No476 () =
    let IN = Console.ReadLine().Split(' ')
    let n = float <| IN.[0]
    let a = float <| IN.[1]
    let x = Console.ReadLine().Split(' ') |> Array.map (fun xi-> Double.Parse xi)

    let getSum s x = s + x
    let average = x |> Array.reduce getSum |> (fun sum-> sum / (float)x.Length)

    if (float)a = average then
        printfn "YES"
    else
        printfn "NO"

    ()

No476 ()