#include <fstream>
#include <vector>
#include <string.h>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");

int n, m, i, j, v[100010], c[100010], st, x, y, u, p, dist[100010], maxim, capat;
vector<int>a[100010];

void bfs(int start){
    u=1;
    p=1;
    c[1]=start;
    v[start]=1;
    while(p<=u){
        int nod1=c[p];
        for(i=0; i<a[nod1].size(); i++){
            int nod2=a[nod1][i];
            if(v[nod2]==0){
                v[nod2]=1;
                dist[nod2]=dist[nod1]+1;
                if(dist[nod2]>maxim){
                    maxim=dist[nod2];
                    capat=nod2;
                }
                u++;
                c[u]=nod2;
            }
        }
        p++;
    }
}

int main(){
    fin>>n;
    for(i=1; i<n; i++){
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    bfs(1);
    memset(v, 0, sizeof(v));
    memset(dist, 0, sizeof(dist));
    maxim=0;
    bfs(capat);
    fout<<dist[capat]+1;
}