import java.util.*;

public class Main {
    static final int BASE = 1000000000;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int d = sc.nextInt();
		long t = sc.nextInt();
		HashMap<Integer, TreeSet<Integer>> ameba = new HashMap<>();
		for (int i = 0; i < n; i++) {
		    int x = sc.nextInt() + BASE;
		    int mod = x % d;
		    int div = x / d;
		    if (!ameba.containsKey(mod)) {
		        ameba.put(mod, new TreeSet<>());
		    }
		    ameba.get(mod).add(div);
		}
		long ans = 0;
		for (TreeSet<Integer> set : ameba.values()) {
		    int left = -1;
		    int right = -1;
		    for (int x : set) {
		        if (left == -1) {
		            left = x;
		            right = x;
		            continue;
		        }
		        if (x - right > 2 * t) {
		            ans += right - left + 1 + 2 * t;
		            left = x;
		            right = x;
		        } else {
		            right = x;
		        }
		    }
		    ans += right - left + 1 + 2 * t;
		}
		System.out.println(ans);
	}
}