let loser h w n =
    let grid = h*w
    let last = (grid%n)
               |> function 
                | x when x=0L -> n
                | x -> x
    last
    
let H,W,N,K = let t = stdin.ReadLine().Split()
                      |> Array.map int64
              in t.[0],t.[1],t.[2],t.[3]
                                    
if loser H W N = K then 
    "YES"
else 
    "NO"
|> printfn "%s"