10 5 5
2 3 4 5 6
 1 1 1
1
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 1000000000000000000 2 1
1 1000000000000000000
 33 32 1
1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
 101 55 10
1 3 5 7 8 9 10 16 18 21 22 23 24 25 27 30 32 35 36 37 38 39 40 43 45 47 49 50 51 52 54 57 59 61 64 66 67 68 69 70 71 72 73 80 83 86 87 88 89 90 91 92 96 97 98
 1000000000000000000 5 1000
1 1000000000 1000000000000 1000000000000000 1000000000000001
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
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 45 43 2
1 2 3 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
 107 20 13
5 9 20 25 26 30 37 45 51 58 62 73 82 87 89 90 99 101 104 106
 3 2 1
1 2
 1000000000 2 1000000000
1 1000000000
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2 3 4 5 6 7 11
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1 2 3 6 7 8 11 12 13
 1000000000000000000 2 1000000000
102306300054748096 267367244641009859
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2 3 4 5 6 15 16
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 1000000000000000000 20 365
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import javafx.util.Pair;
import java.io.*;
import java.math.*;
import java.security.Key;
import java.util.*;
@SuppressWarnings("Duplicates")
// author @mdazmat9
// swing +socket java(udemy)
public class codeforces{
    static Scanner sc = new Scanner(System.in);
    static PrintWriter out = new PrintWriter(System.out);
    public static void main(String[] args) throws IOException {
        int test = 1;
      //  test=sc.nextInt();
        for (int ind = 0; ind < test; ind++) {
            long n=sc.nextLong();
            int m=sc.nextInt();
            long k=sc.nextLong();
            long[]a =longarray(m);
            Queue<Long> queue=new LinkedList<>();
            for(int i=0;i<m;i++){
                 queue.add(a[i]);
            }
            long ans=0;
            long count=0;
            long kk=k;
            while (!queue.isEmpty()){
             //   out.println(queue.peek()+" "+kk);
                count=0;
                while (!queue.isEmpty() && queue.peek()<=kk){
                    count++;
                    queue.poll();
                }
                if(count==0){
                    long mul=(queue.peek()-kk)/k;
                    if((queue.peek()-kk)%k!=0)mul++;
                    kk+=(mul*k);


                }
                else {
                   ans++;
                    kk+=count;
                }
            }
            out.println(ans);

        }
        out.flush();
    }

    static long[] longarray(int n){ long [] a=new long[n];for(int i=0;i<n;i++)a[i]=sc.nextLong();return a; }
    static int[] intarray(int n){ int [] a=new int[n];for(int i=0;i<n;i++)a[i]=sc.nextInt();return a; }
    static ArrayList<Integer> intlist(int n){ArrayList<Integer> list=new ArrayList<>();for(int i=0;i<n;i++)list.add(sc.nextInt());return list; }
    static ArrayList<Long> longlist(int n){ArrayList<Long> list=new ArrayList<>();for(int i=0;i<n;i++)list.add(sc.nextLong());return list; }
    static int[][] read2darray(int n,int m){ int [][] a=new int[n][m];for(int i=0;i<n;i++){ for(int j=0;j<m;j++){ a[i][j]=sc.nextInt(); } }return a; }
    public static double logb( double a, double b ) {return Math.log(a) / Math.log(b); }
    static long fast_pow(long a, long b,long abs) {
        if(b == 0) return 1L;
        long val = fast_pow(a, b / 2,abs);
        if(b % 2 == 0) return val * val % abs;
        else return val * val % abs * a % abs;
    }
    static long abs = (long)1e9 + 7;
    static   void shuffle(int[] a) { int n = a.length;for(int i = 0; i < n; i++) { int r = i + (int) (Math.random() * (n - i));int tmp = a[i];a[i] = a[r];a[r] = tmp; } }
    static long gcd(long a , long b) {
        if(b == 0) return a;
        return gcd(b , a % b);
    }
}


class Scanner {
    public BufferedReader reader;
    public StringTokenizer st;
    public Scanner(InputStream stream) {
        reader = new BufferedReader(new InputStreamReader(stream));
        st = null;
    }
    public String next() {
        while (st == null || !st.hasMoreTokens()) {
            try {
                String line = reader.readLine();
                if (line == null) return null;
                st = new StringTokenizer(line);
            } catch (Exception e) {
                throw (new RuntimeException());
            }
        }
        return st.nextToken();
    }
    public int nextInt() {
        return Integer.parseInt(next());
    }
    public long nextLong() {
        return Long.parseLong(next());
    }
    public double nextDouble() {
        return Double.parseDouble(next());
    }
}
class OutputWriter {
    BufferedWriter writer;
    public OutputWriter(OutputStream stream) {
        writer = new BufferedWriter(new OutputStreamWriter(stream));
    }
    public void print(int i) throws IOException {
        writer.write(i);
    }
    public void print(String s) throws IOException {
        writer.write(s);
    }
    public void print(char[] c) throws IOException {
        writer.write(c);
    }
    public void close() throws IOException {
        writer.close();
    }
}
