#include <bits/stdc++.h>
#include "migrations.h"
using namespace std;
vector<int> g[10001];
vector<int> d;
vector<bool> vis;
void dfs(int u) {
vis[u] = 1;
for (auto v : g[u]) {
if (!vis[v]) {
d[v] = d[u] + 1;
dfs(v);
}
}
}
pair<int, int> get(int N) {
d.assign(N, 0);
vis.assign(N, false);
dfs(0);
int u = max_element(d.begin(), d.end()) - d.begin();
d.assign(N, 0);
vis.assign(N, false);
dfs(u);
int v = max_element(d.begin(), d.end()) - d.begin();
return {u, v};
}
int send_message(int N, int i, int Pi) {
g[i].push_back(Pi);
g[Pi].push_back(i);
if (i == N - 1) {
auto [u, v] = get(N);
if (u != 0) return u;
else return v;
}
return 0;
}
pair<int, int> longest_path(std::vector<int> S) {
int n = S.size();
return {0, S[n - 1]};
}
