/* 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
	{
		// your code goes here
		int[] nums = {0,0,1,1,1,2,2,3,3,4};
		int n = nums.length;
		int k = 1;
		// int i = 0;
 
        for(int i= 1; i<nums.length; i++){
            if(nums[i] != nums[k-1]){
                nums[k++] = nums[i];
            }
        }
		System.out.println(k);
 
	}
}

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