#include <iostream>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;

vector<int> G[100000];
int dp[100000];
int ans;

void dfs(int u, int p) {
  vector<int> a = {0, 0};
  for (int v : G[u]) if (v != p) {
    dfs(v, u);
    dp[u] = max(dp[u], dp[v] + 1);
    a.push_back(dp[v] + 1);
  }
  sort(a.rbegin(), a.rend());
  ans = max(ans, a[0] + a[1]);
}

int main() {
  int N;
  cin >> N;
  for (int i = 0; i < N - 1; i++) {
    int u, v;
    cin >> u >> v;
    u--;
    v--;
    G[u].push_back(v);
    G[v].push_back(u);
  }
  dfs(0, -1);
  cout << N - (ans + 1) << '\n';
}