I submitted a solution for the problem: E. Bertown roads My submission is: 289121858

ideone Link of the same submission: https://ideone.com/Pn4Wdh

The checker comment I got is:

wrong output format Unexpected end of file — int32 expected

Input:

6 8
1 2
2 3
1 3
4 5
4 6
5 6
2 4
3 5

Participant's output:

1 2
1 3

Jury's Answer:

6 4
4 5
5 6
5 3
3 2
2 1
1 3
2 4

But if I run the same code with same input on online compilers and my machine, it produces correct output (not just two lines for the testcase described above). You can check the ideone link I provided, even this one producing the correct output!

I even tried changing the code and replaced the map with set. Here is that submission: 289122463

But the same issue occurs. My code produces only two lines on codeforces but N lines on other compilers.

What am I missing?