My answer is marked wrong
Open the TEST CASES tab to compare your output with the expected output, and DIFFERENCES to see exactly where they differ. Most failures are a missing space, a capital letter or an extra print.
Updated October 17, 2026
A challenge passes only when your program's output matches every test exactly. Here is how to find what is different.
1. Read the test cases
After you press Run Code, open TEST CASES. Each test shows the input, the Expected Output and your Output. When they don't match, open DIFFERENCES to see exactly where.
2. Check the usual causes
- A missing or extra space, or an extra empty line
- Capital letters:
Hellois nothello - Extra
printlines left from testing - Printing when the task asks you to
returna value, or the other way around - Reading input differently from what the task describes
Some tests are hidden, so a program that only prints the expected answers for the visible tests still fails.
3. Ask for help
Ask Bugsy Why did my code fail? It sees your code and your last error. See Bugsy, the AI tutor. You can also reveal a hint, or look at the SOLUTION tab.
Still sure it's right?
Report it from the lesson and choose My answer is correct, but it is not accepted. Keep Include my current code on so we can see exactly what you ran. See Report a problem in a lesson.