#include <iostream>
#include <fstream>
#include <vector>
#define NMAX 100000
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector <int> g[NMAX+1];
int n,vis[NMAX+1],dist=1,maxi,nodem,step=1;
void read() {
    fin>>n;
    int x,y;
    while(fin>>x>>y) {
        g[x].push_back(y);
        g[y].push_back(x);
    }
}
void DFS(int node) {
    vis[node]=step;
    vector <int> ::iterator it;
    for(it=g[node].begin();it!=g[node].end();it++) {
        if(vis[*it]!=step) {
            dist++;
            if(dist>maxi){
                maxi=dist;
                nodem=*it;
            }
            DFS(*it);
            dist--;
        }
    }
}
int main()
{
    read();
    DFS(1);
    maxi=0;
    step++;
    DFS(nodem);
    fout<<maxi;
    return 0;
}