module Main where

import Data.List

eval :: Int -> Int -> [Int] -> [Int]
eval 0 _ = id
eval t d = eval (t - 1) d . f . (>>= \x -> [x+d, x, x-d]) where
    f = g . sort
    g [] = []
    g (x:xs) = x : g (filt (/= x) xs)
    filt _ [] = []
    filt p (y:ys) = if p y then y:ys else filt p ys

main :: IO ()
main = do
        [_, d, t] <- fmap (map read . words) getLine
        xs <- fmap (map read . words) getLine
        print $ length $ eval t d xs