Multi-users get their own specific results from the app

My flask web app is complete but remaining one issue to be fixed: it functions well if only one user uses it. However, if multi users input at the same time, the output is not right. For example, user A inputs a number, if that number meets certain condition, user A shall get score 2 each time of input. If at the same time, there is user B, then, A and B will get scores on top of each other’s score. It means: if User A has already score 4, then User B might get 6. Then A gets 8…. In short, each user can’t get their own specific and right output. It looks like every one on the same page. I tried using sessions to fix the problem but didn’t work. I’m not sure if I made the session coding right or it Is because of my formula coding wrong.