10 5 5
2 3 4 5 6
 1 1 1
1
 1000000000000000000 10 68
9818112234872670 233245257111863071 266483628625876079 375103213040049805 431982380866113633 489732004669478331 501030096787260719 541800997319766183 551892546260532408 696178619227890200
 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
 15 15 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
 21 21 20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
 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
 11 7 3
2 3 4 5 6 7 11
 13 9 4
1 2 3 6 7 8 11 12 13
 1000000000000000000 2 1000000000
102306300054748096 267367244641009859
 16 7 5
2 3 4 5 6 15 16
 35 35 1
1 2 3 4 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 30 31 32 33 34 35
 1000000000000000000 20 365
31881893160049984 103938857870698567 103962228223609431 140762820261865064 175962215264653912 239086305245565642 354522451098745823 383839975876242372 443471287955807705 478923027151493682 511195154588214957 619570919279066139 677571312513476877 705864797651447277 789633853044745934 867300890280086078 883297431113041450 891736036124527038 937306858250803630 990892290394455512

2
 1
 10
 2
 32
 15
 4
 1
 2
 35
 9
 2
 1
 4
 4
 2
 4
 35
 20

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.StringTokenizer;

public class Newbie {

    static class InputReader {
        public BufferedReader br;
        public StringTokenizer token;
        public InputReader(InputStream stream)
        {
            br=new BufferedReader(new InputStreamReader(stream),32768);
            token=null;
        }

        public String next()
        {
            while(token==null || !token.hasMoreTokens())
            {
                try
                {
                    token=new StringTokenizer(br.readLine());
                }
                catch(IOException e)
                {
                    throw new RuntimeException(e);
                }
            }
            return token.nextToken();
        }

        public int nextInt()
        {
            return Integer.parseInt(next());
        }

        public long nextLong()
        {
            return Long.parseLong(next());
        }

        public double nextDouble()
        {
            return Double.parseDouble(next());
        }
    }

    static class card{
        long a;
        int cnt;
        int i;
        public card(long a,int cnt,int i)
        {
            this.a=a;
            this.cnt=cnt;
            this.i=i;
        }
    }

    static class ascend implements Comparator<pair>
    {
        public int compare(pair o1,pair o2)
        {
            if(o1.a!=o2.a)
                return o1.a-o2.a;
            else 
                return o1.b-o2.b;
        }
    }

    static class descend implements Comparator<pair>
    {
        public int compare(pair o1,pair o2)
        {
            if(o1.a!=o2.a){
                return (o1.a-o2.a)*-1;
            } else {
                return (o1.b-o2.b);
            }
        }
    }

    static class extra
    {

        static void shuffle(long a[])
        {
            List<Long> l=new ArrayList<>();
            for(int i=0;i<a.length;i++)
                l.add(a[i]);
            Collections.shuffle(l);
            for(int i=0;i<a.length;i++)
                a[i]=l.get(i);
        }

        static long gcd(long a,long b)
        {
            if(b==0)
                return a;
            else
                return gcd(b,a%b);
        }

        static boolean valid(int i,int j,int r,int c)
        {
            if(i>=0 && i<r && j>=0 && j<c)
                return true;
            else
                return false;
        }

        static boolean v[]=new boolean[100001];
        static List<Integer> l=new ArrayList<>();
        static int t;
        static void seive()
        {
            for(int i=2;i<100001;i++)
            {
                if(!v[i])
                {
                    t++;
                    l.add(i);
                    for(int j=2*i;j<100001;j+=i)
                        v[j]=true;
                }
            }
        }

        static int binary(pair a[],int val,int n)
        {
            int mid=0,l=0,r=n-1,ans=0;
            while(l<=r)
            {
                mid=(l+r)>>1;
                if(a[mid].a==val)
                {
                    r=mid-1;
                    ans=mid;
                }
                else if(a[mid].a>val)
                    r=mid-1;
                else
                {
                    l=mid+1;
                    ans=l;
                }
            }
            return (ans);
        }
    }

    static class pair{
        int a;
        int b;
        public pair(int a,int n)
        {
            this.a=a;
            this.b=n;
        }
    }

    static InputReader sc=new InputReader(System.in);
    static PrintWriter out=new PrintWriter(System.out);
    public static void main(String[] args) {
        solver s=new solver();
        int t=1;
        while(t>0)
        {
            s.solve();
            t--;
        }
    }

    static class solver
    {
        void solve()
        {
          long n=sc.nextLong();
          int m=sc.nextInt();
          long k=sc.nextLong();
          long a[]=new long[m];
          for(int i=0;i<m;i++)
          a[i]=sc.nextLong();
          int ans=0;
          long factor=(a[0]/k)+((a[0]%k!=0)?1:0);
          long lower=factor*k;
          long n1=((n/k)+((n%k!=0)?1:0))*k;
          int j=0,j1=0;
          while(lower<=n1 && j<m && j1<m)
          {
              int c=0,f1=0;
              while(j<m && a[j]<=lower)
              {
                  f1=1;
                  c++;
                  j++;
              }
              j1=j;int f=0;
              while(j1<m && Math.abs(a[j1]-lower)<=c)
              {
                  f=1;
                  j1++;
              }
              if(f==0)
              {
                  lower+=k;
              }
              else
              {
                  ans++;
                  lower+=k;
                  j=j1;
              }
              if(f1==1)
              ans++;
          }
          System.out.println(ans);
        }
    }
}
