static auto fast_io = []

{

    ios::sync_with_stdio(false);

	cout.tie(nullptr);

	cin.tie(nullptr);

	return 0;

}();

class Solution {

public:

    int removeDuplicates(vector<int>& nums)

    {

        int i = 0;

        for (int j = 0; j < nums.size(); ++j)

           if (nums[i] != nums[j])

               nums[++i] = nums[j];

        return i + 1;

    }

};