#include <vector>
#include <algorithm>
#include <iostream>
#define ll long long
using namespace std;
const int N = 100010, M = 1000010;
vector<int>a[N];
bool flag[N];
int path[N],sum,ru[N],chu[N];
int dfs(int x, int pre){
    flag[x] = 1;
    for (auto v:a[x]){
        if (!flag[v]){
            int index = dfs(v, x);
            if (!index)continue;
            if (index != -1)path[++sum] = v;
            if (index == v)return -1;
            else  return index;

        }
        else if (v != pre){
            path[++sum] = v;
            return v;
        }
    }
}
int main(){
    int n,ans=0;
    cin >> n;
    for (int i = 1; i <=n; ++i){
        int u, v;
        cin >> u >> v;
        a[u].push_back(v);
        a[v].push_back(u);
        chu[u]++;
        chu[v]++;
    }
    int f=0,num=0;
    dfs(1, -1);
    chu[path[1]]--;
    chu[path[2]]--;
    for (int i = 1; i <= n; i++) {
        if (chu[i] >= 5) {
            f = 1;
            break;
        }
        else if (chu[i] >= 4) {
            num++;
        }
    }
    if (!f)ans += n - num;
    chu[path[2]]++;
    chu[path[3]]--;
    f = num = 0;
    for (int i = 1; i <= n; i++) {
        if (chu[i] >= 5) {
            f = 1;
            break;
        }
        else if (chu[i] >= 4)
            num++;
    }
    if (!f)ans += n - num;
    f = num = 0;
    chu[path[1]]++;
    chu[path[2]]--;
    for (int i = 1; i <= n; i++) {
        if (chu[i] >= 5) {
            f = 1;
            break;
        }
        else if (chu[i] >= 4)
            num++;
    }
    if (!f)ans += n - num;
    cout <<ans<< endl;
}