import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.TreeSet;

public class Main {
	
	public static long MOD = 1000000007;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final int N = sc.nextInt();
		final long D = sc.nextLong();
		final long T = sc.nextLong();
		
		HashMap<Long, TreeSet<Long>> mods = new HashMap<Long, TreeSet<Long>>();
		for(int i = 0; i < N; i++){
			final long X = sc.nextLong();
			final long mod = X % D;
			
			if(!mods.containsKey(mod)){
				mods.put(mod, new TreeSet<Long>());
			}
			mods.get(mod).add(X);
		}
		
		long answer = 0;
		for(final Entry<Long, TreeSet<Long>> entry : mods.entrySet()){
			final long mod = entry.getKey();
			final ArrayList<Long> list = new ArrayList<Long>(entry.getValue());
			
			if(list.size() == 1){ answer += (2 * T + 1); continue; }
			
			answer += T;
			//System.out.println(answer);
			for(int fst = 0; fst < list.size() - 1; fst++){
				final int snd = fst + 1;
				final long diff = Math.abs(list.get(snd) - list.get(fst)) / D - 1;
				final long min = Math.min(diff, 2 * T);
				
				answer += min + 1;
			}
			answer += T + 1;
		}
		
		System.out.println(answer);
	}
}