It means exactly what is says:

• Unexpected end of file — the output file ended before it should've, i.e. you printed too few tokens.
• int32 expected — the next token of the output should've been an integer instead of the output ending.

This is one test case where your code fails:

Input:
1
3
2
1 2
2
1 2
2
1 2

Excpected Output:
-1

Your Output:

Your code outputs nothing for the above test case. Can you see why this happens? I can help you more if you can't find the cause of this.