#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

int n;
vector<int> edges[100000];
int dist[100000];

void dfs(int v, int par = -1, int d = 0) {
  dist[v] = d;
  for (int w: edges[v]) {
    if (w != par)
      dfs(w, v, d+1);
  }
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  cin >> n;
  REP (i, n-1) {
    int v, w;
    cin >> v >> w;
    --v, --w;
    edges[v].push_back(w);
    edges[w].push_back(v);
  }

  dfs(0);
  int x = max_element(dist, dist + n) - dist;
  dfs(x);
  int d = *max_element(dist, dist + n);
  cout << n - d - 1 << endl;

  return 0;
}