NZEC for CHEFXCHG in Python

long-contest

#1

For CHEFXCHG even the most naive solution in python3/pypy3 is giving a Run-time Error.
NZEC: https://www.codechef.com/viewsolution/24263935

However, the following code gives WA as expected.
WA: https://www.codechef.com/viewsolution/24263912

The WA is understandable but I just don’t get why it gives me NZEC.