#include <bits/stdc++.h>

 #define dbg(x) cout << #x << "=" << x << endl

 #define eps 1e-8

 #define pi acos(-1.0)

 using namespace std;

 typedef long long LL;

 template<class T>inline void read(T &res)

 {

     char c;T flag=;

     while((c=getchar())<''||c>'')if(c=='-')flag=-;res=c-'';

     while((c=getchar())>=''&&c<='')res=res*+c-'';res*=flag;

 }

 namespace _buff {

     const size_t BUFF =  << ;

     char ibuf[BUFF], *ib = ibuf, *ie = ibuf;

     char getc() {

         if (ib == ie) {

             ib = ibuf;

             ie = ibuf + fread(ibuf, , BUFF, stdin);

         }

         return ib == ie ? - : *ib++;

     }

 }

 int qread() {

     using namespace _buff;

     int ret = ;

     bool pos = true;

     char c = getc();

     for (; (c < '' || c > '') && c != '-'; c = getc()) {

         assert(~c);

     }

     if (c == '-') {

         pos = false;

         c = getc();

     }

     for (; c >= '' && c <= ''; c = getc()) {

         ret = (ret << ) + (ret << ) + (c ^ );

     }

     return pos ? ret : -ret;

 }

 const int maxn = 2e5 + ;

 int head[maxn << ], edge[maxn << ], nxt[maxn << ];

 int w[maxn << ];

 int vis[maxn];

 int dis[maxn];

 int n, cnt;

 void BuildGraph(int u, int v, int c) {

     cnt++;

     edge[cnt] = v;

     nxt[cnt] = head[u];

     w[cnt] = c;

     head[u] = cnt;

 }

 int bfs(int x) {

     memset(vis, , sizeof(vis));

     memset(dis, , sizeof(dis));

     int pos = ;

     queue <int> q;

     q.push(x);

     vis[x] = ;

     int u;

     while(!q.empty()) {

         u = q.front();

         //dbg(u);

         q.pop();

         for (int i = head[u]; i; i = nxt[i]) {

             int v = edge[i];

             int d = w[i];

             if(vis[v])

                 continue;

             else {

                 dis[v] = dis[u] + d;

                 vis[u] = ;

                 if(dis[v] > dis[pos]) {

                     pos = v;

                 }

                 q.push(v);

             }

         }

     }

     return pos;

 }

 int d1[maxn], d2[maxn];

 int main()

 {

     read(n);

     int a, b;

     for ( int i = ; i < n; ++i ) {

         read(a);

         read(b);

         BuildGraph(a, b, );

         BuildGraph(b, a, );

     }

     int p1, p2;

     p1 = bfs();

     p2 = bfs(p1);

     for ( int i = ; i <= n; ++i ) {

         d1[i] = dis[i];

     }

     int p3 = bfs(p2);

     for ( int i = ; i <= n; ++i ) {

         d2[i] = dis[i];

     }

     int p4 = ;

     for ( int i = ; i <= n; ++i ) {

         if(d1[i] + d2[i] > d1[p4] + d2[p4] && i != p1 && i != p2) {

             p4 = i;

         }

     }

     int ans = d1[p4]+d2[p4]+d1[p2];

     //dbg(ans);

     printf("%d\n",ans / );

     printf("%d %d %d\n",p1,p2,p4);

     return ;

 }