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

int main(){
    int n;
    cin >> n;
    vector<int> v[n];
    int a, b;
    for(int i = 0; i < n-1; i++){
        cin >> a >> b;
        a--, b--;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    vector<bool> visit(n, 0);
    queue<int> q;
    int t;
    q.push(0);
    while(!q.empty()){
        int x = q.front();  q.pop();
        if(visit[x])    continue;
        t = x;
        visit[x] = true;
        for(int next : v[x]){
            if(!visit[next])    q.push(next);
        }
    }
    for(int i = 0; i < n; i++)  visit[i] = false;
    queue<pair<int,int>> pq;
    pq.push({t, 0});
    int cost;
    while(!pq.empty()){
        auto x = pq.front(); pq.pop();
        int i = x.first;
        if(visit[i])    continue;
        cost = x.second;
        visit[i] = true;
        for(int next : v[i]){
            if(!visit[next])    pq.push({next, cost+1});
        }
    }
    cout << n-1 - cost << endl;
    return 0;
}