#include <bits/stdc++.h>

#define CEIL(a,b) ((a) / (b) + ((a) % (b) == 0 ? 0 : 1))

using namespace std;
using ll = long long;
using pii = pair<int, int>;

constexpr int MOD = int(1e9 + 7);
constexpr int INF = int(1e9 + 1);
constexpr ll LLINF = ll(4 * 1e18 + 1);
// constexpr int INF = 2147483647; // 2 * 1e9
// constexpr ll LLINF = 9223372036854775807; // 9 * 1e18

const int dx[] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
const int dy[] = {0, 1, 0, -1, 1, 1, -1, -1, 0};

struct Edge{
    int to;
    int cost;
};
vector<Edge> g[100000];

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(10);
    int n;
    cin >> n;
    for(int i = 0; i < n - 1; ++i){
        int a, b;
        cin >> a >> b;
        --a; --b;
        g[a].push_back({b, 1});
        g[b].push_back({a, 1});
    }

    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> que;
    vector<int> d(n, INF);
    d[0] = 0;
    que.push({int(0), 0});
    
    while(!que.empty()){
        int c = que.top().first;
        int v = que.top().second;
        que.pop();
        
        for(auto && e : g[v]){
            if(d[e.to] > c + e.cost){
                d[e.to] = c + e.cost;
                que.push({d[e.to], e.to});
            }
        }
    }
    
    int ma = -1, mai = -1;
    for(int i = 0; i < n; ++i){
        if(ma < d[i]){
            ma = d[i];
            mai = i;
        }
    }
    
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> que2;
    vector<int> d2(n, INF);
    d2[mai] = 0;
    que2.push({int(0), mai});
    
    while(!que2.empty()){
        int c = que2.top().first;
        int v = que2.top().second;
        que2.pop();
        
        for(auto && e : g[v]){
            if(d2[e.to] > c + e.cost){
                d2[e.to] = c + e.cost;
                que2.push({d2[e.to], e.to});
            }
        }
    }
    
    int ma2 = 0;
    for(int i = 0; i < n; ++i){
        ma2 = max(ma2, d2[i]);
    }
    
    cout << n - ma2 - 1 << "\n";
    
    return 0;
}