#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-9;
const int inf = 2000000000;
const long long infLL = 9000000000000000000;
template <typename first, typename second>
ostream &operator<<(ostream &os, const pair<first, second> &p) {
  return os << "(" << p.first << ", " << p.second << ")";
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "{";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  return os << "}";
}
template <typename T>
ostream &operator<<(ostream &os, const set<T> &v) {
  os << "[";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin()) os << ",";
    os << *it;
  }
  return os << "]";
}
template <typename T>
ostream &operator<<(ostream &os, const multiset<T> &v) {
  os << "[";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  return os << "]";
}
template <typename first, typename second>
ostream &operator<<(ostream &os, const map<first, second> &v) {
  os << "[";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin()) os << ", ";
    os << it->first << " = " << it->second;
  }
  return os << "]";
}
void faltu() { cerr << '\n'; }
template <typename T>
void faltu(T a[], int n) {
  for (int i = 0; i < n; ++i) cerr << a[i] << ' ';
  cerr << '\n';
}
template <typename T, typename... hello>
void faltu(T arg, const hello &...rest) {
  cerr << arg << ' ';
  faltu(rest...);
}
const int mx = 2e5 + 5;
vector<int> adjlist[mx];
int n;
bool isleaf[mx];
int deg[mx];
struct info {
  int leaf, child, dist;
};
bool cmp(const info &lhs, const info &rhs) { return lhs.dist > rhs.dist; }
vector<info> dp[mx];
void dfs(int u, int par) {
  vector<info> store;
  store.push_back({u, u, 0});
  for (auto v : adjlist[u]) {
    if (v == par) continue;
    dfs(v, u);
    info temp = dp[v][0];
    ++temp.dist;
    temp.child = v;
    store.push_back(temp);
  }
  sort(store.begin(), store.end(), cmp);
  while (store.size() > 3) store.pop_back();
  dp[u] = store;
}
int ans = 0;
vector<int> vec;
void dfs2(int u, int par) {
  if (dp[u].size() >= 3) {
    if (ans < dp[u][0].dist + dp[u][1].dist + dp[u][2].dist) {
      ans = dp[u][0].dist + dp[u][1].dist + dp[u][2].dist;
      vec.clear();
      vec.push_back(dp[u][0].leaf);
      vec.push_back(dp[u][1].leaf);
      vec.push_back(dp[u][2].leaf);
    }
  }
  for (auto v : adjlist[u]) {
    if (v == par) continue;
    for (int i = 0; i < dp[u].size(); ++i) {
      if (dp[u][i].child == v) continue;
      info temp = dp[u][i];
      temp.child = u;
      ++temp.dist;
      dp[v].push_back(temp);
      sort(dp[v].begin(), dp[v].end(), cmp);
      dfs2(v, u);
      break;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  cin >> n;
  for (int i = 0; i < n - 1; ++i) {
    int a, b;
    cin >> a >> b;
    adjlist[a].push_back(b);
    adjlist[b].push_back(a);
    ++deg[a];
    ++deg[b];
  }
  for (int i = 1; i <= n; ++i) {
    if (deg[i] == 1) isleaf[i] = 1;
  }
  dfs(1, 0);
  dfs2(1, 0);
  cout << ans << '\n';
  for (int i = 0; i < vec.size(); ++i) cout << vec[i] << " ";
  cout << '\n';
}
