#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
long long powmod(long long a, long long b, long long MOD) {
  if (a == 0ll) {
    return 0ll;
  }
  a %= MOD;
  long long ans = 1;
  while (b) {
    if (b & 1) {
      ans = ans * a % MOD;
    }
    a = a * a % MOD;
    b >>= 1;
  }
  return ans;
}
void Pv(const vector<int> &V) {
  int Len = int(V.size());
  for (int i = 0; i < Len; ++i) {
    printf("%d", V[i]);
    if (i != Len - 1) {
      printf(" ");
    } else {
      printf("\n");
    }
  }
}
void Pvl(const vector<long long> &V) {
  int Len = int(V.size());
  for (int i = 0; i < Len; ++i) {
    printf("%lld", V[i]);
    if (i != Len - 1) {
      printf(" ");
    } else {
      printf("\n");
    }
  }
}
inline long long readll() {
  long long tmp = 0, fh = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') fh = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar();
  return tmp * fh;
}
inline int readint() {
  int tmp = 0, fh = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') fh = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar();
  return tmp * fh;
}
const int maxn = 1000010;
const int inf = 0x3f3f3f3f;
int n;
std::vector<int> son1[maxn];
std::vector<int> son2[maxn];
int a, b, c;
int ans = 0;
int key = 0;
int m = -1;
void dfs1(int x, int pre, int cnt) {
  if (cnt > m) {
    m = cnt;
    if (key == 0) {
      a = x;
    } else if (key == 1) {
      b = x;
    }
  }
  for (auto y : son1[x]) {
    if (y != pre) {
      dfs1(y, x, cnt + 1);
    }
  }
}
stack<int> st;
int belong[maxn];
void dfs2(int x, int pre) {
  st.push(x);
  if (x == b) {
    while (!st.empty()) {
      belong[st.top()] = n + 1;
      st.pop();
    }
    key = 2;
    return;
  }
  for (auto y : son1[x]) {
    if (y != pre) {
      dfs2(y, x);
    }
    if (key == 2) {
      return;
    }
  }
  st.pop();
}
void dfs3(int x, int pre, int cnt) {
  if (cnt > m) {
    m = cnt;
    c = x;
  }
  for (auto y : son2[x]) {
    if (y != pre) {
      dfs3(y, x, cnt + 1);
    }
  }
}
int main() {
  n = readint();
  for (int i = 1; i <= n - 1; i++) {
    int x, y;
    x = readint();
    y = readint();
    son1[x].push_back(y);
    son1[y].push_back(x);
  }
  m = -1;
  dfs1(1, 0, 0);
  key = 1;
  m = -1;
  dfs1(a, 0, 0);
  ans += m;
  for (int i = 1; i <= n; i++) {
    belong[i] = i;
  }
  dfs2(a, 0);
  for (int i = 1; i <= n; i++) {
    for (auto y : son1[i]) {
      if (belong[y] != belong[i]) {
        son2[belong[y]].push_back(belong[i]);
      }
    }
  }
  m = -1;
  dfs3(n + 1, 0, 0);
  ans += m;
  printf("%d\n", ans);
  if (c == n + 1) {
    for (int i = 1; i <= n; i++) {
      if (i == a || i == b) {
        continue;
      }
      c = i;
      break;
    }
  }
  printf("%d %d %d\n", a, b, c);
  return 0;
}
