#include <bits/stdc++.h>
#define endl '\n'
#define int long long
using namespace std;
const int N = 100005;
const int inf = 1e9;

int n;
int ans;

int rd[N];
int tmp[N];
bitset<N>flag;
int num3, num4;

queue<int>q;
vector<int>to[N];

struct edge {
	int x, y;
}e[N];
vector<edge>ee;

signed main() {
	ios::sync_with_stdio(false),cin.tie(0);
	cin >> n;
	for (int i = 1; i <= n; ++i) {
		int x, y;
		cin >> x >> y;
		e[i].x = x; e[i].y = y;
		to[x].push_back(y);
		to[y].push_back(x);
		rd[x]++; rd[y]++;
	}
	
	for (int i = 1; i <= n; ++i) {
		if (rd[i] <= 3) num3++;
		else if (rd[i] <= 4) num4++;
	}
	
	for (int i = 1; i <= n; ++i) tmp[i] = rd[i];
	for (int i = 1; i <= n; ++i) {
		if (tmp[i] == 1) {
			q.push(i);
			flag[i] = 1;
		}
	}
	
	while (!q.empty()) {
		int u = q.front(); q.pop();
		for (auto v : to[u]) {
			if (--tmp[v] == 1) {
				q.push(v);
				flag[v] = 1;
			}
		}
	}
	
	for (int i = 1; i <= n; ++i) {
		if (!flag[e[i].x] && !flag[e[i].y]) {
			ee.push_back(e[i]);
		}
	}
	
	for (edge e : ee) {
		if (rd[e.x] == 4) {num3++; num4--;}
		if (rd[e.y] == 4) {num3++; num4--;}
		if (rd[e.x] == 5) {num4++;}
		if (rd[e.y] == 5) {num4++;}
		
		if (num3 + num4 == n) ans += num3;
		
		if (rd[e.x] == 4) {num3--; num4++;}
		if (rd[e.y] == 4) {num3--; num4++;}
		if (rd[e.x] == 5) {num4--;}
		if (rd[e.y] == 5) {num4--;}
	}
	
	cout << ans << endl;
	
	return 0;
}

/*
0 0 0 1 2 3
*/