Problem Windy Cannon has a judging error. My first submission received the message “internal error (15)”. After a minor correction, a subsequent submission received “accepted”. Reviewing the existing submissions, starting about May 2021, a wrong answer for the problem will result in a SPOJ internal error. Prior to this date, “wrong answer” is the submission result. After this date, “internal error (15)” is the submission result. Accepted is still accepted.