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.math.BigInteger; 
import java.util.*;



//Mann Shah [ DAIICT ].
//fast io

public class Main {
	static int mod = (int) (1e9+7);
	static InputReader in;
    static PrintWriter out;
    
    		
		public static void main(String args[] )  {
			
		  in = new InputReader(System.in);
	      out = new PrintWriter(System.out);
	     
	      long n = in.nextLong();
	      long m = in.nextLong();
	      long k = in.nextLong();
	      
	      long[] a = new long[(int)m];
	      for(int i=0;i<m;i++) {
	    	  	a[i] = in.nextLong();
	      }
	      int c=0;
	      int i=0;
	      while(i<m){
	    	  	c++;
	    	  	long val = (((a[i]-i-1)/k)+1)*k;
	    	  	long low = i;
	    	  	long high = m-1;
	    	  	long res  = i;
	    	  	while(low<=high) {
	    	  		long mid = low + (high-low)/2;
	    	  		if(a[(int)mid]-i<=val) {
	    	  			res = mid;
	    	  			low = mid+1;
	    	  		}
	    	  		else {
	    	  			high = mid -1;
	    	  		}
	    	  	}
	    	  	i=(int)res+1;
	      }
	      
	      
	      
//	      int c=0;
//	      int[] f = new int[(int)(n/k)+1];
//	      for(int i=0;i<m;i++) {
//	    	  		f[(a[i]-i)/k]++;
//	    	  		if((a[i]-i)/k != a[i]/k && a[i]){
//	    	  			c++;
//	    	  		}
//	      }
//	      for(int i=0;i<(int)n/k;i++) {
//	    	  	if(f[i]==0) {
//	    	  		break;
//	    	  	}
//	    	  	else {
//	    	  		c++;
//	    	  	}
//	      }
	      out.print(c);
	     
	      
	     out.close();
		}
		

		
		static class InputReader
	    {

	        private final InputStream stream;
	        private final byte[] buf = new byte[8192];
	        private int curChar, snumChars;
	        private SpaceCharFilter filter;

	        public InputReader(InputStream stream)
	        {
	                this.stream = stream;
	        }

	        public int snext()
	        {
	                if (snumChars == -1)
	                        throw new InputMismatchException();
	                if (curChar >= snumChars)
	                {
	                        curChar = 0;
	                        try
	                        {
	                                snumChars = stream.read(buf);
	                        } catch (IOException e)
	                        {
	                                throw new InputMismatchException();
	                        }
	                        if (snumChars <= 0)
	                                return -1;
	                }
	                return buf[curChar++];
	        }

	        public int nextInt()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                {
	                        c = snext();
	                }
	                int sgn = 1;
	                if (c == '-')
	                {
	                        sgn = -1;
	                        c = snext();
	                }
	                int res = 0;
	                do
	                {
	                        if (c < '0' || c > '9')
	                                throw new InputMismatchException();
	                        res *= 10;
	                        res += c - '0';
	                        c = snext();
	                } while (!isSpaceChar(c));
	                return res * sgn;
	        }

	        public long nextLong()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                {
	                        c = snext();
	                }
	                int sgn = 1;
	                if (c == '-')
	                {
	                        sgn = -1;
	                        c = snext();
	                }
	                long res = 0;
	                do
	                {
	                        if (c < '0' || c > '9')
	                                throw new InputMismatchException();
	                        res *= 10;
	                        res += c - '0';
	                        c = snext();
	                } while (!isSpaceChar(c));
	                return res * sgn;
	        }

	        public int[] nextIntArray(int n)
	        {
	                int a[] = new int[n];
	                for (int i = 0; i < n; i++)
	                {
	                        a[i] = nextInt();
	                }
	                return a;
	        }

	        public long[] nextLongArray(int n)
	        {
	                long a[] = new long[n];
	                for (int i = 0; i < n; i++)
	                {
	                        a[i] = nextLong();
	                }
	                return a;
	        }

	        public String readString()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                {
	                        c = snext();
	                }
	                StringBuilder res = new StringBuilder();
	                do
	                {
	                        res.appendCodePoint(c);
	                        c = snext();
	                } while (!isSpaceChar(c));
	                return res.toString();
	        }

	        public String nextLine()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                        c = snext();
	                StringBuilder res = new StringBuilder();
	                do
	                {
	                        res.appendCodePoint(c);
	                        c = snext();
	                } while (!isEndOfLine(c));
	                return res.toString();
	        }

	        public boolean isSpaceChar(int c)
	        {
	                if (filter != null)
	                        return filter.isSpaceChar(c);
	                return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	        }

	        private boolean isEndOfLine(int c)
	        {
	                return c == '\n' || c == '\r' || c == -1;
	        }

	        public interface SpaceCharFilter
	        {
	                public boolean isSpaceChar(int ch);
	        }

	    }
		
}

//For Pair sorting

//Arrays.sort(arr,new Comparator<Pair>() {
//		@Override public int compare(Pair p1, Pair p2) 
//{ 
//    return p1.x - p2.x; 
//} 
//});



//Pair arr[] = new Pair[n]; 
//arr[0] = new Pair(10, 20); 
class Pair { 
    int x; 
    int y; 
  
    // Constructor 
public Pair(int x, int y) 
    { 
        this.x = x; 
        this.y = y; 
    } 
} 
// class Compare { 
//	  //void return by default.
//     public  Pair[] compare(Pair arr[], int n) 
//    { 
//        // Comparator to sort the pair according to first element.
//        Arrays.sort(arr, new Comparator<Pair>() { 
//            @Override public int compare(Pair p1, Pair p2) 
//            { 
//                return p1.x - p2.x; 
//            } 
//        }); 
//        
//        
//        return arr;
//       /* for (int i = 0; i < n; i++) { 
//            System.out.print(arr[i].x + " " + arr[i].y + " "); 
//        } 
//        System.out.println(); */
//    } 
//} 
//



class couple implements Comparable<couple>
{ int x,y;
  public couple(int m,int f) {
 	 x=m;
 	 y=f;
  }
	public int compareTo(couple o) {
		
		 
		return x-o.x;
	}  
}
