Hello!

We've examined the issue and confirmed that the official solution and some outputs in the last subtask were indeed incorrect due to an overflow.

We've looked at the contestants' submissions and discovered that all that received full points had the same error as the official solution and none of the submissions with a lower score was unfairly penalized while correctly handling the overflow issue with 128-bit arithmetic. Since we believe this would be discovered and corrected by the contestants during the contest and big-int arithmetic was not the point of the task, we will keep the results as they are.

Thanks again for reporting the issue.

Tomaž Hočevar