#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <algorithm>
#include <set>
#include <map>
#include <bitset>
#include <cmath>
#include <functional>
#include <iomanip>
#define vll vector<ll>
#define vvvl vector<vvl>
#define vvl vector<vector<ll>>
#define VV(a, b, c, d) vector<vector<d>>(a, vector<d>(b, c))
#define VVV(a, b, c, d) vector<vvl>(a, vvl(b, vll (c, d)));
#define re(c, b) for(ll c=0;c<b;c++)
#define rep(a,b,c) for(ll a=b;a<c;a++)
#define all(obj) (obj).begin(), (obj).end()
typedef long long int ll;
typedef long double ld;
using namespace std;

void get(vll &a){re(i,a.size()) scanf("%lld",&a[i]);}
void get(vvl &a){re(i,a.size()) re(j,a[0].size()) scanf("%lld",&a[i][j]);}
void print(vll &a){re(i,a.size()) cout<<a[i]<<(i==a.size()-1?"\n":" ");}
void print(vvl &a){re(i,a.size()) re(j,a[0].size())cout<<a[i][j]<<(j==a[0].size()-1?"\n":" ");}
//_____________________________________________________________
const int MAX_NODE=1000000;

vvl G = VV(MAX_NODE, 0, 0, ll);
void dfs(int from, int now){
  //std::cout << now << '\n';
  for(int i=0;i<G[now].size();i++) {
    if(from == G[now][i]) continue;
    dfs(now, G[now][i]);
  }
}
void treeDFS(int from, int current, int dist, int &maxDist, int &maxVertex) {
    if (dist > maxDist) maxDist = dist, maxVertex = current;
    for (auto to : G[current]) {
        if (to == from) continue;
        treeDFS(current, to, dist + 1, maxDist, maxVertex);
    }
}
int getTreeDiameter(int s) {
    int start = s, end = 0, maxDist = 0;
    treeDFS(-1, start, 0, maxDist, end);
    start = end, end = 0, maxDist = 0;
    treeDFS(-1, start, 0, maxDist, end);
    //printf("start: %d, end: %d, diameter: %d\n", start, end, maxDist);
    return maxDist;
}
//_____________________________________________________________
int main(int argc, char const *argv[]) {
  ll n;std::cin >> n;
  re(i, n-1){
    ll a, b;std::cin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  cout << n - 1 - getTreeDiameter(1) << "\n";
  return 0;
}