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

public class Solution {
    public static int removeDuplicates(int[] nums) {
        int r=0;
        int len=nums.length;
        int i=0,j=0;
        if(len<2)
            return 0;
        int cmp=nums[0];
        int c=0;
        nums[j]=nums[0];
        j++;
        for(i=1;i<len;i++)
        {
            if(cmp!=nums[i])
            {
                cmp=nums[i];
                nums[j]=nums[i];
                j++;
            }
            else
            {
                c++;
            }
        }
        r=len-c;
        return r;
    }
    public static void main(String[] args)
    {
        int[] a={1,1,1,1,4,5};
        System.out.println(removeDuplicates(a));
        int[] b={1,1,1,5};
        System.out.println(removeDuplicates(b));
    }
}