#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10;
int head[maxn], dis[maxn], ans, f[maxn], maxdot, cnt;
bool vis[maxn];
struct Edge {
  int u, v, w, net;
} edge[maxn << 1];
struct Node {
  int x, step;
  Node() {}
  Node(int x, int step) : x(x), step(step) {}
};
queue<Node> q;
void addedge(int u, int v, int w) {
  edge[cnt].u = u;
  edge[cnt].v = v;
  edge[cnt].w = w;
  edge[cnt].net = head[u];
  head[u] = cnt++;
}
void dfs(int u, int fa) {
  f[u] = fa;
  for (int i = head[u]; i != -1; i = edge[i].net) {
    int v = edge[i].v, w = edge[i].w;
    if (v == fa) continue;
    dis[v] = dis[u] + w;
    if (ans <= dis[v]) {
      ans = dis[v];
      maxdot = v;
    }
    dfs(v, u);
  }
}
void bfs() {
  while (!q.empty()) {
    Node now = q.front();
    q.pop();
    if (ans < now.step) {
      ans = now.step;
      maxdot = now.x;
    }
    for (int i = head[now.x]; i != -1; i = edge[i].net) {
      int v = edge[i].v, w = edge[i].w;
      if (!vis[v]) {
        vis[v] = true;
        q.push(Node(v, now.step + w));
      }
    }
  }
}
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i <= n; ++i) head[i] = -1;
  for (int i = 1; i < n; ++i) {
    int u, v;
    scanf("%d%d", &u, &v);
    addedge(u, v, 1);
    addedge(v, u, 1);
  }
  dfs(1, -1);
  int s = maxdot;
  dis[s] = 0;
  ans = 0;
  dfs(s, -1);
  int e = maxdot;
  ans = 0;
  for (int i = e; i != -1; i = f[i]) {
    vis[i] = true;
    q.push(Node(i, 0));
  }
  bfs();
  int len;
  if (maxdot == s || maxdot == e) {
    maxdot = f[e];
    len = dis[e];
  } else
    len = dis[e] + ans;
  printf("%d\n", len);
  printf("%d %d %d\n", s, e, maxdot);
  return 0;
}
