Untitled

#include 
#include 
#include 
#include 
using namespace std;
typedef long long ll;
const int maxn = 2e5 + 10;
vector graph[maxn];
int subtree[maxn];
int n, m;
void subtree_size(int node, int prev) {
    subtree[node] = 1;
    
    for(int neighbour : graph[node]) {
        if(neighbour != prev) {
            subtree_size(neighbour, node);
            subtree[node] += subtree[neighbour];
        }
    }
}
int centroid(int node, int prev) {
    for(int neighbour : graph[node]) {
        if(neighbour != prev) {
            if(subtree[neighbour] * 2 > n) {
                return centroid(neighbour, node);
            }
        }
    }
    return node;
}
int main() {
    ios_base::sync_with_stdio(false);
    cin >> n;
    for(int i = 0; i < n - 1; i++) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    subtree_size(0, -1);
    cout << centroid(0, -1) + 1 << endl;
    return 0;
}