I use Python2. But I always get eternal "Waiting..." with even sample script. I get message "Only secure content is displayed" after "Submit". So I click "Show all content" and but I get RE with even sample script.
Make sure your program is in accordance with the input format.
If you submit the "A+B Problem" sample code on these test problems you will certainly get RE. Because the sample code expects lines containing exactly 2 integers while the test problems don't.
I see. Understanding. Thank you