Getting NZEC in this problem

My code is here for ZUBREACH and I am always getting NZEC may I know why?
https://www.codechef.com/viewsolution/17952668
please tell me
question https://www.codechef.com/status/ZUBREACH/

According to the constraints given, the length of the sequence can be 0 as well. Your code gives NZEC in that case.