#include <bits/stdc++.h> using namespace std; #define pb push_back using pr = pair<int, int>; const int INF = 1e9+7, MOD = 1e9+7; int n; vector<int> edge; bitset<1000000> crit; void Init(int N_) { n = N_; } void Link(int A, int B) { edge[A]++; edge[B]++; if (crit[A] && edge[B] > 3) crit[A] = 0; if (crit[B] && edge[A] > 3) crit[B] = 0; } int CountCritical() { return crit.count(); }