Question: https://mirror.codeforces.com/contest/1702/problem/E Submission: https://mirror.codeforces.com/contest/1702/submission/266327665

So first i've checked if the frequencies of all elmenents is exactly two. Second check: If node 1 is connected to node 2 and 3. Then node 2 and 3 cannot be connected. If this is true for all nodes, return yes. Otherwise output No. Idk why this is failing.