#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
const long long L = 2e5 + 5;
vector<long long> ad[L];
long long vis[L];
long long mxd = -1;
long long mxi;
void dfs(long long ind, long long d) {
  vis[ind] = 1;
  if (d > mxd) {
    mxd = d;
    mxi = ind;
  }
  for (auto v : ad[ind]) {
    if (!vis[v]) {
      dfs(v, d + 1);
    }
  }
}
long long src;
long long trg;
long long sub[L];
long long dfs2(long long ind) {
  vis[ind] = 1;
  if ((long long)(ad[ind].size()) == 1 && ind != src) {
    if (ind == trg)
      return sub[ind] = 1;
    else
      return sub[ind] = 0;
  }
  long long f = 0;
  for (auto v : ad[ind]) {
    if (!vis[v]) {
      if (f == 0) f = dfs2(v);
    }
  }
  return sub[ind] = f;
}
void dfs3(long long ind, long long d) {
  vis[ind] = 1;
  if (d > mxd) {
    mxd = d;
    mxi = ind;
  }
  for (auto v : ad[ind]) {
    if (!vis[v]) {
      dfs3(v, d + 1 - sub[v]);
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, u, v;
  cin >> n;
  for (long long i = 0; i < n - 1; i++) {
    cin >> u >> v;
    ad[u].push_back(v);
    ad[v].push_back(u);
  }
  dfs(1, 0);
  long long ind1 = mxi;
  mxd = -1;
  mxi = 0;
  for (long long i = 1; i <= n; i++) vis[i] = 0;
  dfs(ind1, 0);
  long long finald = mxd;
  long long ind2 = mxi;
  long long ind3;
  src = ind1;
  trg = ind2;
  mxd = -1;
  mxi = 0;
  for (long long i = 1; i <= n; i++) vis[i] = 0;
  dfs2(ind1);
  for (long long i = 1; i <= n; i++) vis[i] = 0;
  mxd = -1;
  mxi = 0;
  dfs3(ind1, 0);
  if (mxi != ind1 && mxi != ind2) {
    cout << finald + mxd << '\n';
    cout << ind1 << ' ' << ind2 << ' ' << mxi << '\n';
  } else {
    cout << finald << '\n';
    for (long long i = 1; i <= n; i++) {
      if (i != ind1 && i != ind2) {
        cout << i << ' ' << ind1 << ' ' << ind2 << '\n';
        return 0;
      }
    }
  }
  return 0;
}
