#include <bits/stdc++.h>
using namespace std;
const int mxN = 2e5;
int ans = 0;
int from[mxN];
bool vis[mxN];
vector<int> adj[mxN];
pair<int, int> furthest(int u, int from = -1, int d = 0) {
  pair<int, int> res = {d, u};
  for (int v : adj[u]) {
    if (v != from && !vis[v]) {
      pair<int, int> p = furthest(v, u, d + 1);
      if (p.first > res.first) {
        res.first = p.first;
        res.second = p.second;
      }
    }
  }
  return res;
}
void dfs(int u, int par = -1) {
  from[u] = par;
  for (int v : adj[u]) {
    if (v != par) {
      dfs(v, u);
    }
  }
}
vector<int> path(int a, int b) {
  memset(from, -1, sizeof(from));
  dfs(a);
  vector<int> p;
  while (b != -1) {
    p.push_back(b);
    b = from[b];
  }
  return p;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i < n; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  int a = furthest(0).second;
  int b = furthest(a).second;
  int dist = furthest(a).first;
  vector<int> p = path(a, b);
  int c, mx = 0;
  for (int i = 0; i < n; i++) {
    if (i != a && i != b) {
      c = i;
    }
  }
  for (int i : p) {
    vis[i] = true;
  }
  for (int i : p) {
    if (furthest(i).first > mx) {
      mx = furthest(i).first;
      c = furthest(i).second;
    }
  }
  dist += mx;
  a++, b++, c++;
  assert(a && b && c && dist > 0);
  cout << dist << '\n' << a << ' ' << b << ' ' << c << '\n';
}
