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.*;
import java.util.*;
import java.math.*;
import java.text.*;
import java.util.regex.*;

import java.awt.Point;

public final class Main{
	long mod = 1000000007;
	
    public static void main(String[] args)throws Exception{
        new Main().run();
    }
    
    {
        st = null;
        br = new BufferedReader(new InputStreamReader(System.in));
    }
    
    void run()throws Exception{
		long n=nl(), m=nl(), k=nl();
		long[] spi = new long[(int)m];
		for(int i=0; i<m; i++)spi[i] = nl();
		
		int di=0, res=0;
		long low=1, high=k, removed=0;
		while(true){
			res++;
			//adjust ptrs
			//pl("cur di : " + di);
			while(true){
				if((spi[di]-removed) >= low && (spi[di]-removed) <= high){
					break;
				}else{
					low  += k;
					high += k;
				}
			}
			//pl("Valid index : " + low + " " + high);
			
			//check elements
			for(int i=di; i<m; i++){
				if(!((spi[i]-removed) >= low && (spi[i]-removed) <= high)){
					removed = di = i;
					if(i == spi.length - 1){res++; di++;}
					break;
				}else{
					//pl("Removed item : " + spi[i]);
					if(i == spi.length-1){
						di = spi.length;
						break;
					}
				}
			}
			if(res == 7)break;
			if(di == spi.length)break;
		}
		pl(res);
	}
    
    //------------------------------------------------------------------------------------------------//
    //------------------------------------------------------------------------------------------------//
    BufferedReader br;
    StringTokenizer st;
        
    String nextToken()throws Exception{
        if(st == null || !st.hasMoreTokens()){st = new StringTokenizer(br.readLine(), " ");}
        return st.nextToken();
    }
        
    int ni()throws Exception{return Integer.parseInt(nextToken());}
    long nl()throws Exception{return Long.parseLong(nextToken());}
    double nd()throws Exception{return Double.parseDouble(nextToken());}
    String nt()throws Exception{return nextToken();}
    String ns()throws Exception{return br.readLine();}
    
    void p(Object o){System.out.print(o);}
    void pl(Object o){System.out.println(o);}
	void pl(int[] a){System.out.println(Arrays.toString(a));}
    //------------------------------------------------------------------------------------------------//
    //------------------------------------------------------------------------------------------------//
    
    long min(long... nos){
        if(nos.length == 0)return -1;
        long min = nos[0];
        for(int i=1; i<nos.length; i++)min = Math.min(min, nos[i]);
        return min;
    }
    
    long max(long... nos){
        if(nos.length == 0)return -1;
        long max = nos[0];
        for(int i=1; i<nos.length; i++)max = Math.max(max, nos[i]);
        return max;
    }
}
