#include <bits/stdc++.h>
using namespace std;
const int Nmax = 1e6 + 5;
int n;
bool big = 0, cycle = 0;
vector<int> cand;
vector<pair<int,int>> edges;
int grad[5][Nmax];
bool ok[Nmax];
int ans;
struct FO
{
int t[Nmax];
void init()
{
int i;
for(i=0; i<n; ++i) t[i] = i;
}
int boss(int x)
{
if(t[x] == x) return x;
return t[x] = boss(t[x]);
}
bool unite(int x, int y)
{
x = boss(x); y = boss(y);
if(x == y) return 0;
t[x] = y;
return 1;
}
} forest[5];
void Init(int N)
{
n = N;
ans = n;
forest[4].init();
int i, j;
for(i=0; i<n; ++i)
for(j=0; j<5; ++j)
grad[j][i] = 0, ok[i] = 0;
}
void transf(int node)
{
big = 1;
int i;
for(auto it : edges)
if(it.first == node)
cand.push_back(it.second);
else if(it.second == node)
cand.push_back(it.first);
cand.push_back(node);
int id = -1;
for(auto el : cand)
{
++id;
ok[el] = 1;
forest[id].init();
for(auto it : edges)
if(it.first != el && it.second != el)
{
++grad[id][it.first], ++grad[id][it.second];
ok[el] &= forest[id].unite(it.first, it.second);
}
}
ans = 0;
id = -1;
for(auto it : cand)
{
++id;
for(i=0; i<n; ++i)
ok[it] &= (grad[id][i] <= 2);
if(ok[it]) ++ans;
}
}
void Link(int A, int B)
{
edges.push_back({A, B});
if(!big)
{
++grad[4][A];
++grad[4][B];
if(grad[4][A] == 3) transf(A);
else if(grad[4][B] == 3) transf(B);
else
if(!forest[4].unite(A, B))
{
if(!cycle)
{
cycle = 1;
int i;
ans = 0;
for(i=0; i<n; ++i)
if(forest[4].boss(i) == forest[4].boss(A)) ok[i] = 1, ++ans;
}
else ans = 0;
}
return;
}
int id = -1;
for(auto el : cand)
{
++id;
if(!ok[el]) continue;
if(el != A && el != B)
{
++grad[id][A];
++grad[id][B];
ans --;
ok[el] &= forest[id].unite(A, B);
ok[el] &= (grad[id][A] <= 2 && grad[id][B] <= 2);
ans += ok[el];
}
}
}
int CountCritical()
{
return ans;
}
