SPOJPT07Z.cpp

//
// Created by Anas on 05-08-2020.
//

#include <bits/stdc++.h>
using namespace std;

vector<int> adj[10000];
vector<bool>v(10000, false);
int cnt;
int bfs(int a,int n){
    cnt=0;
    queue<int>q;
    int level[10000]={0};
    q.push(a);
    for(int i=0;i<10000;i++)
        v[i]=false;

    int f=0;
    while(!q.empty()){
       f=q.front();
        v[f]=true;
        q.pop();


         //cout<<f<<" ";
            int flg=1;

        for(int i=0;i<adj[f].size();i++) {
            if(!v[adj[f][i]]) {
                if(flg)
                cnt++;
                flg=0;
                level[adj[f][i]] = level[f] + 1;
                q.push(adj[f][i]);
            }
        }



        }

    return f;


    }



void solve(int n){
    int x=0,y=0;
   for(int i=0;i<n-1;i++){
       cin>>x>>y;

       adj[x].push_back(y);
       adj[y].push_back(x);

   }
   int k=bfs(1,n);
    // cout<<k<<endl;
    cnt=0;
   k= bfs(k,n);
    //cout<<k<<endl;
   cout <<cnt<<endl;

}

int main(){
    int n;
    cin>>n;
    solve(n);

    return 0;

}