import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;

public class Main {

	/**
	 * This class represents a problem setting.
	 */
	class Problem implements IProblem {

		int[] NDT;
		int[] X;
		
		@Override
		public void set(ProblemReader reader) throws IOException {
			NDT = reader.nextIntArray();
			X = reader.nextIntArray();
		}
		
		@Override
		public String toString() {
			// TODO
			return null;
		}
	}
	
	/**
	 * Solver for the problem.
	 * It's the most important part of codes in this file.
	 */
	class Solver implements IProblemSolver<Problem> {

		@Override
		public String solve(Problem problem) {
			int N = problem.NDT[0], D = problem.NDT[1], T = problem.NDT[2];
			int[] X = problem.X;
			return StringUtils.toString(solve(N, D, T, X));
		}
		
		private long solve(int N, int D, int T, int[] X) {
			HashMap<Integer, Intervals> intervals = new HashMap<>();
			for (int i = 0; i < N; i++) {
				int x = X[i];
				if (x < 0) {
					x = X[i] + ((-X[i]) / D + 1) * D;
				}
				int r = x % D;
				Intervals intrs = intervals.get(r);
				if (intrs == null) {
					intervals.put(r, intrs = new Intervals());
				}
				long s = X[i] - D * (long)T;
				long t = X[i] + D * (long)T;
				intrs.intervals.add(new Interval(s, t));
			}
			long res = 0;
			for (Intervals intrs : intervals.values()) {
				intrs.merge();
				res += intrs.num(D);
			}
			return res;
		}
		
		class Interval implements Comparable<Interval> {
			
			long s, t;
			
			Interval(long s, long t) {
				this.s = s;
				this.t = t;
			}
			
			Interval merge(Interval interval) {
				if (t < interval.s || interval.t < s) {
					return null;
				}
				return new Interval(Math.min(s, interval.s), Math.max(t, interval.t));
			}
			
			long num(int D) {
				return (t - s) / D + 1;
			}
			
			@Override
			public int compareTo(Interval interval) {
				if (s < interval.s) {
					return -1;
				} else if (s > interval.s) {
					return 1;
				} else if (t < interval.t) {
					return -1;
				} else if (t > interval.t) {
					return 1;
				} else {
					return 0;
				}
			}
		}
		
		class Intervals {
			
			List<Interval> intervals = new ArrayList<>();
			
			void merge() {
				if (intervals.size() > 0) {
					List<Interval> nintervals = new ArrayList<>();
					Collections.sort(intervals);
					Interval interval = intervals.get(0);
					for (int i = 1; i < intervals.size(); i++) {
						Interval interval2 = intervals.get(i);
						Interval ninterval = interval.merge(interval2);
						if (ninterval == null) {
							nintervals.add(interval);
							interval = interval2;
						} else {
							interval = ninterval;
						}
					}
					nintervals.add(interval);
					intervals = nintervals;
				}
			}
			
			long num(int D) {
				long num = 0;
				for (Interval interval : intervals) {
					num += interval.num(D);
				}
				return num;
			}
		}
	}
	
	/**
	 * This class is a solver to confirm the main solver.
	 * This solver often works only for a problem with a small number setting.
	 */
	class Solver2 implements IProblemSolver<Problem> {

		@Override
		public String solve(Problem problem) {
			// TODO
			return null;
		}
	}
	
	class Factory implements IProblemFactory<Problem> {

		@Override
		public Problem newProblem() {
			// TODO
			return null;
		}

		@Override
		public Problem newProblem(ProblemReader reader) throws IOException {
			Problem problem = new Problem();
			problem.set(reader);
			return problem;
		}
	}
	
	ProblemProcessor<Problem> processor;
	
	Main() {
		Init();
	}
	
	void Init() {
		ProblemProcessorConfig<Problem> config = new ProblemProcessorConfig<>();
		
		config.factory = new Factory();
		config.solver = new Solver();
		config.solver2 = new Solver2();
		
		processor = new ProblemProcessor<Problem>(config);
	}
	
	void process(String mode) throws IOException {
		processor.process(mode);
	}
	
	public static void main(String args[]) throws IOException {
		String mode = "solve";
		new Main().process(mode);
	}
	
/*
	Common library
*/
	
	interface IProblem {
		
		abstract void set(ProblemReader reader) throws IOException;
	}
	
	interface IProblemFactory<P extends IProblem> {
		
		abstract P newProblem();
		abstract P newProblem(ProblemReader reader) throws IOException;
	}
	
	interface IProblemSolver<P extends IProblem> {
		
		abstract String solve(P problem);
	}
	
	class ProblemReader {
		
		BufferedReader br = null;
		
		ProblemReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}
		
		int nextInt() throws IOException {
			return StringUtils.toInt(br.readLine());
		}
		
		long nextLong() throws IOException {
			return StringUtils.toLong(br.readLine());
		}
		
		double nextDouble() throws IOException {
			return StringUtils.toDouble(br.readLine());
		}
		
		String nextString() throws IOException {
			return br.readLine();
		}
		
		int[] nextIntArray() throws IOException {
			return StringUtils.toIntArray(br.readLine());
		}
		
		long[] nextLongArray() throws IOException {
			return StringUtils.toLongArray(br.readLine());
		}
		
		double[] nextDoubleArray() throws IOException {
			return StringUtils.toDoubleArray(br.readLine());
		}
		
		String[] nextStringArray() throws IOException {
			return StringUtils.toStringArray(br.readLine());
		}
		
		int[] nextIntArray(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++) {
				a[i] = nextInt();
			}
			return a;
		}
		
		long[] nextLongArray(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++) {
				a[i] = nextLong();
			}
			return a;
		}
		
		double[] nextDoubleArray(int n) throws IOException {
			double[] a = new double[n];
			for (int i = 0; i < n; i++) {
				a[i] = nextDouble();
			}
			return a;
		}
		
		String[] nextStringArray(int n) throws IOException {
			String[] strs = new String[n];
			for (int i = 0; i < n; i++) {
				strs[i] = nextString();
			}
			return strs;
		}
		
		int[][] nextIntArray2(int n) throws IOException {
			int[][] a = new int[n][];
			for (int i = 0; i < n; i++) {
				a[i] = nextIntArray();
			}
			return a;
		}
		
		long[][] nextLongArray2(int n) throws IOException {
			long[][] a = new long[n][];
			for (int i = 0; i < n; i++) {
				a[i] = nextLongArray();
			}
			return a;
		}
		
		double[][] nextDoubleArray2(int n) throws IOException {
			double[][] a = new double[n][];
			for (int i = 0; i < n; i++) {
				a[i] = nextDoubleArray();
			}
			return a;
		}
		
		String[][] nextStringArray2(int n) throws IOException {
			String[][] strs = new String[n][];
			for (int i = 0; i < n; i++) {
				strs[i] = nextStringArray();
			}
			return strs;
		}
		
		void close() throws IOException {
			if (br != null) {
				br.close();
			}
		}
	}
	
	class ProblemCreator<P extends IProblem> {
		
		IProblemFactory<P> factory;
		
		ProblemCreator(IProblemFactory<P> factory) {
			this.factory = factory;
		}
		
		void create() throws FileNotFoundException {
			P problem = factory.newProblem();
			System.out.println(problem.toString());
		}
	}
	
	class ProblemSolverComparator<P extends IProblem> {
		
		IProblemFactory<P> factory;
		IProblemSolver<P> solver1, solver2;
		
		ProblemSolverComparator(IProblemFactory<P> factory, IProblemSolver<P> solver1, IProblemSolver<P> solver2) {
			this.factory = factory;
			this.solver1 = solver1;
			this.solver2 = solver2;
		}
		
		void compare() throws IOException {
			ProblemReader reader = null;
			try {
				reader = new ProblemReader();
				P problem = factory.newProblem(reader);
				String res1 = solver1.solve(problem);
				String res2 = solver2.solve(problem);
				if (res1.equals(res2)) {
					System.out.println(res1);
				} else {
					System.err.println(res1 + " " + res2);
				}
			} finally {
				if (reader != null) {
					reader.close();
				}
			}
		}
	}
	
	class ProblemAnswerer<P extends IProblem> {
		
		IProblemFactory<P> factory;
		IProblemSolver<P> solver;
		
		ProblemAnswerer(IProblemFactory<P> factory, IProblemSolver<P> solver) {
			this.factory = factory;
			this.solver = solver;
		}
		
		void answer() throws IOException {
			ProblemReader reader = null;
			try {
				reader = new ProblemReader();
				P problem = factory.newProblem(reader);
				String res = solver.solve(problem);
				System.out.println(res);
			} finally {
				if (reader != null) {
					reader.close();
				}
			}
		}
	}
	
	class ProblemProcessorConfig<P extends IProblem> {
		
		IProblemFactory<P> factory;
		
		IProblemSolver<P> solver, solver2;
	}
	
	class ProblemProcessor<P extends IProblem> {
		
		ProblemProcessorConfig<P> config;
		
		ProblemCreator<P> creator;
		ProblemSolverComparator<P> comparator;
		ProblemAnswerer<P> answerer;
		
		ProblemProcessor(ProblemProcessorConfig<P> config) {
			this.config = config;
			creator = new ProblemCreator<P>(config.factory);
			comparator = new ProblemSolverComparator<P>(config.factory, config.solver, config.solver2);
			answerer = new ProblemAnswerer<P>(config.factory, config.solver);
		}
		
		void process(String mode) throws IOException {
			switch (mode) {
			case "create":
				creator.create();
				break;
			case "debug":
				comparator.compare();
				break;
			case "solve":
				answerer.answer();
				break;
			}
		}
	}
	
	static class StringUtils {
		
		static String toString(int a) {
			return String.valueOf(a);
		}
		
		static String toString(long a) {
			return String.valueOf(a);
		}
		
		static String toString(double a) {
			return String.valueOf(a);
		}
		
		static String toString(String str) {
			return str;
		}
		
		static String toString(int[] a) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < a.length; i++) {
				if (i < a.length - 1) {
					sb.append(a[i] + " ");
				} else {
					sb.append(a[i]);
				}
			}
			return sb.toString();
		}
		
		static String toString(long[] a) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < a.length; i++) {
				if (i < a.length - 1) {
					sb.append(a[i] + " ");
				} else {
					sb.append(a[i]);
				}
			}
			return sb.toString();
		}
		
		static String toString(double[] a) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < a.length; i++) {
				if (i < a.length - 1) {
					sb.append(a[i] + " ");
				} else {
					sb.append(a[i]);
				}
			}
			return sb.toString();
		}
		
		static String toString(String[] strs) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < strs.length; i++) {
				if (i < strs.length - 1) {
					sb.append(strs[i] + " ");
				} else {
					sb.append(strs[i]);
				}
			}
			return sb.toString();
		}
		
		static String toString(int[][] a) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < a.length; i++) {
				for (int j = 0; j < a[i].length; j++) {
					if (j < a[i].length - 1) {
						sb.append(a[i][j] + " ");
					} else {
						sb.append(a[i][j]);
					}
				}
				sb.append("\n");
			}
			sb.setLength(sb.length() - 1);
			return sb.toString();
		}
		
		static String toString(long[][] a) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < a.length; i++) {
				for (int j = 0; j < a[i].length; j++) {
					if (j < a[i].length - 1) {
						sb.append(a[i][j] + " ");
					} else {
						sb.append(a[i][j]);
					}
				}
				sb.append("\n");
			}
			sb.setLength(sb.length() - 1);
			return sb.toString();
		}
		
		static String toString(double[][] a) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < a.length; i++) {
				for (int j = 0; j < a[i].length; j++) {
					if (j < a[i].length - 1) {
						sb.append(a[i][j] + " ");
					} else {
						sb.append(a[i][j]);
					}
				}
				sb.append("\n");
			}
			sb.setLength(sb.length() - 1);
			return sb.toString();
		}
		
		static String toString(String[][] a) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < a.length; i++) {
				for (int j = 0; j < a[i].length; j++) {
					if (j < a[i].length - 1) {
						sb.append(a[i][j] + " ");
					} else {
						sb.append(a[i][j]);
					}
				}
				sb.append("\n");
			}
			sb.setLength(sb.length() - 1);
			return sb.toString();
		}
		
		static int toInt(String s) throws IOException {
			return Integer.parseInt(s);
		}
		
		static long toLong(String s) throws IOException {
			return Long.parseLong(s);
		}
		
		static double toDouble(String s) throws IOException {
			return Double.parseDouble(s);
		}
		
		static int[] toIntArray(String s) throws IOException {
			String[] tokens = s.split(" ");
			int[] a = new int[tokens.length];
			for (int i = 0; i < tokens.length; i++) {
				a[i] = Integer.parseInt(tokens[i]);
			}
			return a;
		}
		
		static long[] toLongArray(String s) throws IOException {
			String[] tokens = s.split(" ");
			long[] a = new long[tokens.length];
			for (int i = 0; i < tokens.length; i++) {
				a[i] = Long.parseLong(tokens[i]);
			}
			return a;
		}
		
		static double[] toDoubleArray(String s) throws IOException {
			String[] tokens = s.split(" ");
			double[] a = new double[tokens.length];
			for (int i = 0; i < tokens.length; i++) {
				a[i] = Double.parseDouble(tokens[i]);
			}
			return a;
		}
		
		static String[] toStringArray(String s) throws IOException {
			return s.split(" ");
		}
	}
}