Possible Int/Long Conflict? (ADDNATRL)


I used the Gauss summation method for ADDNATRL (Add Natural Numbers). I think the math itself is fine. To my understanding, long was discontinued in Python 3, so I have used type int in my solution. Test cases work as expected, including the maximum N = 10^9, but when I submitted my solution, it was marked as incorrect. I am not sure what I am doing wrong. Any advice would be greatly appreciated.


N = int(input())