#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fi first
#define se second
#define ll long long
#define ld long double
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define mpp make_pair
#define ve vector
using namespace std;
using namespace __gnu_pbds;
template<class T> using oset = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
const ll inf = 1e18; const int iinf = 1e9;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T> inline bool chmin(T& a, T b) { return (a > b ? a = b, 1 : 0); }
template <typename T> inline bool chmax(T& a, T b) { return (a < b ? a = b, 1 : 0); }
const int N = 2e5 + 10;
ve<int> gr[N];
set<int> *s[N];
int sz[N], nxt[N];
inline void dfs(int v, int p) {
sz[v] = 1; nxt[v] = -1;
for (auto &to : gr[v]) {
if (to == p) continue;
dfs(to, v);
sz[v] += sz[to];
if (!~nxt[v] || sz[nxt[v]] < sz[to]) nxt[v] = to;
}
}
int n;
int res;
ve<int>* sub[N];
int fenw[N];
inline void upd(int i, int x) { for (i += 3; i < N; i += i & -i) fenw[i] += x; }
inline int get(int i) { int ans = 0; for (i += 3; i; i -= i & -i){ans += fenw[i];} return ans; }
inline int get(int l, int r) { return get(r) - get(l - 1); }
inline void dfs1(int v, int p, bool keep = 0) {
for (auto &to : gr[v]) {
if (to == p || to == nxt[v]) continue;
dfs1(to, v, 0);
}
if (~nxt[v]) dfs1(nxt[v], v, 1);
if (!~nxt[v]) sub[v] = new ve<int>;
else sub[v] = sub[nxt[v]];
for (auto &to : gr[v]) {
if (to == p || to == nxt[v]) continue;
for (auto &u : *sub[to]) {
// sz[w] in [sz[u] - x, sz[u] + x]
// sz[w] in [n - 2 * sz[u] - x, n - 2 * s[u] + x]
// sz[w] in 1/2 * [n - sz[u] - x, n - sz[u] + x]
const int &S = sz[u];
int l = 0, r = res - 1, m, ans = res;
while (l <= r) {
m = l + r >> 1;
int L = max({0, S - m, n - 2 * S - m, (n - S - m + 1) / 2});
int R = min({n, S + m, n - 2 * S + m, (n - S + m) / 2});
if (L > R) l = m + 1;
else {
if (get(L, R)) ans = m, r = m - 1;
else l = m + 1;
}
}
chmin(res, ans);
}
for (auto &u : *sub[to]) {
(*sub[v]).pb(u);
upd(sz[u], +1);
}
}
upd(sz[v], +1);
(*sub[v]).pb(v);
if (!keep) {
for (auto &u : *sub[v]) {
upd(sz[u], -1);
}
}
}
inline void dfs2(int v, int p) {
const int S = sz[v];
int l = 0, r = res - 1, m, ans = res;
while (l <= r) {
m = l + r >> 1;
int L = max({0, 2 * S - m, n - S - m, (n + S - m + 1) / 2});
int R = min({n, 2 * S + m, n - S + m, (n + S + m) / 2});
if (L > R) l = m + 1;
else {
if (get(L, R)) ans = m, r = m - 1;
else l = m + 1;
}
}
chmin(res, ans);
upd(S, +1);
for (auto &to : gr[v]) {
if (to == p) continue;
dfs2(to, v);
}
upd(S, -1);
}
inline void solve() {
cin >> n; res = n - 2;
for (int i = 1; i < n; ++i) {
int v, u;
cin >> v >> u, --v, --u;
gr[v].pb(u), gr[u].pb(v);
}
dfs(0, 0);
dfs1(0, 0), dfs2(0, 0);
cout << res;
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int q = 1; // cin >> q;
while (q--) solve();
cerr << fixed << setprecision(3) << "Time execution: " << (double)clock() / CLOCKS_PER_SEC << endl;
}
