#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<unordered_set>
using namespace std;

int main(){
    int N;
    cin >> N;
    vector<vector<int>> G(N);
    
    int start = -1;
    for(int i=0;i<N-1;i++){
        int a,b;
        cin >> a >> b;
        a--, b--;
        G[a].push_back(b);
        G[b].push_back(a);
    }

    queue<int> one;
    for(int i=0;i<N;i++){
        if(G[i].size() == 1) one.push(i);
    }

    unordered_set<int> road;
    int ans = 0;

    while(!one.empty()){
        int start = one.front();
        one.pop();
        if(road.count(start)) continue;

        queue<pair<int,int>> Q;
        vector<bool> visited(N,false);
        vector<int> back(N,-1);

        Q.push({start,0});
        visited[start] = true;
        int end = start;

        int dia = 0;
        while(!Q.empty()){
            pair<int,int> p = Q.front();
            Q.pop();

            bool ok = true;
            for(int to : G[p.first]){
                if(road.count(to)) ok = false;
            }

            if(!ok) break;

            for(int to : G[p.first]){
                if(visited[to]) continue;
                visited[to] = true;
                if(dia <= p.second+1){
                    back[to] = p.first;
                    end = to;
                    dia = p.second+1;
                }
                Q.push({to,p.second+1});
            }
        }

        while(end != start){
            road.insert(end);
            end = back[end];
        }
        road.insert(start);

        ans++;
    }
    ans--;

    cout << ans << endl;
}