#include<iostream>
#include<vector>
#include<string>
#include<cmath>
#include<algorithm>
#include<functional>
#include<numeric>
#include<queue>
#include<stack>
#include<map>
#include<unordered_map>
#include<set>
#include<bitset>
#include<random>

#pragma region
using namespace std;
#define FOR(i,r,n) for(ll i = (ll)(r); i < (ll)(n); i++)
#define rep(i,n) FOR(i,0LL,n)
#define RFOR(i,r,n) for(ll i=(ll)(n-1);i>=r;i--)
#define rrep(i,n) RFOR(i,0LL,n)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define COUNT(a,y,x) upper_bound(all(a), y) - lower_bound(all(a), x)
#define UNIQUE(a) sort(all(a)); a.erase(unique(all(a)), a.end())
#define pb push_back
typedef long long int ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<string> vs;
typedef map<ll, ll> MAP;
const ll inf = 2222222222222222222LL;
const ll mod = 1000000007LL;

ll n = 0, m = 0, ans = 0, tmp = 0, ma = -inf, mi = inf;
string s;
bool ok;
ll dx[9] = { 0,1,-1,0,0,1,1,-1,-1 }, dy[9] = { 0,0,0,1,-1,1,-1,1,-1 };
#define endl '\n'
#pragma endregion
#define MAX 222222


vll edge[MAX];
ll root = 0, dist = 0;

void dfs(ll cur,ll pre,ll dep) {
  if (dep > dist) {
    root = cur;
    dist = dep;
  }
  rep(i, edge[cur].size()) {
    ll to = edge[cur][i];
    if (to == pre) continue;
    dfs(to, cur, dep + 1);
  }
}


int main(void) {
  ios::sync_with_stdio(false); cin.tie(0);



  cin >> n;
  rep(i, n) {
    ll x, y;
    cin >> x >> y;
    edge[x].pb(y);
    edge[y].pb(x);
  }
  dfs(1, 0, 0);
  tmp = root;
  root = 0; dist = 0;
  dfs(tmp, 0, 0);
  cout << n - dist - 1 << endl;


  return 0;
}