#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
const int INF = 1e9;
int n;
vector<vi> adj;
vi tin, tout, sz, euler;
int timer;
// segment-tree
vector<vi> seg;
// DFS1: Euler tour + tính sz[u]
void dfs(int u, int p){
tin[u] = ++timer;
euler[timer] = u;
sz[u] = 1;
for(int v: adj[u]){
if(v==p) continue;
dfs(v, u);
sz[u] += sz[v];
}
tout[u] = timer;
}
// build on A[i] = sz[ euler[i] ]
void build(int idx, int l, int r){
if(l==r){
seg[idx] = vi{ sz[euler[l]] };
} else {
int m=(l+r)>>1;
build(idx<<1, l, m);
build(idx<<1|1, m+1, r);
auto &L=seg[idx<<1], &R=seg[idx<<1|1];
seg[idx].resize(L.size()+R.size());
merge(L.begin(),L.end(), R.begin(),R.end(), seg[idx].begin());
}
}
// trên node idx[l..r], tìm predecessor ≤target
int queryPred(int idx,int l,int r,int L,int R,int target){
if(R<l||r<L) return -INF;
if(L<=l&&r<=R){
auto &v=seg[idx];
auto it=upper_bound(v.begin(), v.end(), target);
if(it==v.begin()) return -INF;
--it;
return *it;
}
int m=(l+r)>>1;
return max(
queryPred(idx<<1,l,m,L,R,target),
queryPred(idx<<1|1,m+1,r,L,R,target)
);
}
// tìm successor ≥target
int querySucc(int idx,int l,int r,int L,int R,int target){
if(R<l||r<L) return +INF;
if(L<=l&&r<=R){
auto &v=seg[idx];
auto it=lower_bound(v.begin(), v.end(), target);
if(it==v.end()) return +INF;
return *it;
}
int m=(l+r)>>1;
return min(
querySucc(idx<<1,l,m,L,R,target),
querySucc(idx<<1|1,m+1,r,L,R,target)
);
}
// gom cả pred/succ ra vector
void queryClosest(int L, int R, int target, vector<int> &out){
if(L>R) return;
int p = queryPred(1,1,n,L,R,target);
if(p>0) out.push_back(p);
int s = querySucc(1,1,n,L,R,target);
if(s<INF) out.push_back(s);
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin>>n;
adj.assign(n+1,{});
for(int i=1,x,y;i<n;i++){
cin>>x>>y;
adj[x].push_back(y);
adj[y].push_back(x);
}
tin.assign(n+1,0);
tout.assign(n+1,0);
sz.assign(n+1,0);
euler.assign(n+1,0);
timer=0;
dfs(1,0);
seg.assign(4*(n+1),{});
build(1,1,n);
int ans = n;
// xét mỗi u=2..n (cắt cạnh cha–u)
for(int u=2;u<=n;u++){
int s = sz[u];
int r = n - s;
// --- nested: trong subtree u ---
if(tin[u]+1 <= tout[u]){
vector<int> cand;
int tgt = s/2;
queryClosest(tin[u]+1, tout[u], tgt, cand);
for(int a: cand){
int b = s - a;
int mx = max({a,b,r});
int mn = min({a,b,r});
ans = min(ans, mx - mn);
}
}
// --- disjoint: ngoài subtree u ---
if(r>0){
vector<int> cand;
int tgt = r/2;
// prefix [1..tin[u]-1]
queryClosest(1, tin[u]-1, tgt, cand);
// suffix [tout[u]+1..n]
queryClosest(tout[u]+1, n, tgt, cand);
for(int a: cand){
int b = r - a;
int mx = max({a,b,s});
int mn = min({a,b,s});
ans = min(ans, mx - mn);
}
}
}
cout<<ans<<"\n";
return 0;
}
