/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
	  int[] arr = {0,0,1,1,1,2,2,3,3,4};
	  System.out.println(unique(arr));
	  
	}
	
	static int unique(int[] nums){
	 int n = nums.length;
     int j = 1;
     int i = 0;
      while(j < n){
        
        if(nums[j]!= nums[i]){
            i++;
            nums[i] = nums[j];
        }
      j++;
      }
      return i+1;
    }
}