#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10;
const long long MOD = 1e9 + 7;
const long long INF = 1e18;
inline long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
inline int lb(int x) { return x & -x; }
long long qpow(long long base, int n) {
  if (base == 0) return 0;
  long long ans = 1;
  while (n) {
    if (n & 1) ans *= base;
    n >>= 1;
    base *= base;
  }
  return ans;
}
int n;
vector<int> adj[maxn];
int dis[maxn];
bool vis[maxn];
int from = 1, to = 1, third, ans, tmp;
void dfs(int rt, int fa, int d) {
  for (auto x : adj[rt]) {
    if (x == fa) continue;
    dfs(x, rt, d + 1);
  }
  dis[rt] = d;
}
bool color(int rt, int fa) {
  if (rt == to) {
    vis[rt] = true;
    return true;
  }
  for (auto x : adj[rt]) {
    if (x == fa) continue;
    vis[rt] = color(x, rt);
    if (vis[rt]) return true;
  }
  return false;
}
void DFS(int rt, int fa, int d) {
  if (d > tmp) {
    third = rt;
    tmp = d;
  }
  for (auto x : adj[rt]) {
    if (x == fa || vis[x]) continue;
    DFS(x, rt, d + 1);
  }
}
int main() {
  scanf("%d", &n);
  int u, v;
  for (int i = (2); i <= (n); ++i) {
    scanf("%d%d", &u, &v);
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  dfs(1, -1, 0);
  for (int i = 2; i <= n; ++i)
    if (dis[i] > dis[to]) to = i;
  memset(dis, 0, sizeof(dis));
  dfs(to, -1, 0);
  for (int i = 2; i <= n; ++i)
    if (dis[i] > dis[from]) from = i;
  ans += dis[from];
  color(from, -1);
  memset(dis, 0, sizeof(dis));
  for (int i = (1); i <= (n); ++i) {
    if (vis[i]) DFS(i, -1, 0);
  }
  ans += tmp;
  if (!third) {
    for (int i = (1); i <= (n); ++i)
      if (i != from && i != to) {
        third = i;
        break;
      }
  }
  printf("%d\n%d %d %d\n", ans, from, to, third);
}
