I was participating in the Educational Round the other day. I was trying 915E. I submitted this code but ended up with an RTE on the very first case. Whereas this code doesn't cause any problem on various online IDEs, I am getting RTE on Codeforces. So I debugged a while and ended up with this code. From what I see, its not inputting just after one iteration.

I am all lost here. Anything on this will be so much of help right now! Thanks in advance.

I joined Codeforces with this account on Sept. 8, 2017. While creating the account, I think I saw something like "You can't change your handle after first 7 days". Again, I mention that I 'think' I saw this. Now that I want to change my handle, can I do it? If yes, how so? Thanks in advance :)