#include <fstream>
#include <vector>
#include <queue>
#include <cstring>

#define NMAX 100005
using namespace std;

ifstream f("darb.in");
ofstream g("darb.out");

struct lan{
    int y, dist;
};
vector<int>graph[NMAX];
queue<lan>Q;
int viz[NMAX];
int dist[NMAX];
int n, x, y;

void citire(){
    f>>n;
    for(int i=1; i<=n-1; i++){
        f>>x>>y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
}
lan bfs(int nod_start){
    memset(viz, 0, sizeof(viz));

    Q.push({nod_start, 1});
    viz[nod_start] = 1;
    lan nod;

    while(!Q.empty()){
        lan el = Q.front();
        nod = el;
        Q.pop();
        for(auto &v:graph[el.y])
            if(viz[v] == 0){
                Q.push({v, el.dist+1});
                viz[v] = 1;
            }
    }
    return nod;
}
int main()
{
    citire();
    lan u1 = bfs(1);
    lan fin = bfs(u1.y);
    g<<fin.dist;
    return 0;
}