source_code: import java.util.*;
  import java.io.*;
  public class Solution{
      
      public static long page(long p,long k){
          
          return (p-1)/k;
          
      }
      
      public static void main(String[] args) throws Exception {
          Scanner sc = new Scanner(System.in);
          
          long n = sc.nextLong();
          int m = sc.nextInt();
          long k = sc.nextLong();
          long[] p = new long[m];
          long del = 0;
          long nb = 1;
          int op = 0;
          for(int i=0;i<m;i++) p[i] = sc.nextLong();
          for(int i=1;i<m;i++){
              if(page(p[i]-del,k)!=page(p[i-1]-del,k)){
                  
                  del += nb;
                  nb = 1;
                  op++;
                  
              }else{
                  nb++;
                  
              }
          }
          if(nb!=0) op++;
          
          System.out.println(op);
          
      }
      
  }