#include <fstream>
#include <vector>
using namespace std;

vector <int> gr[100010];
int levelmax = -1;
int best = -1;
bool viz[100010];
ifstream f("darb.in");
ofstream g("darb.out");
void dfs(int node, int lvl){
    viz[node] = true;
    if(lvl > levelmax){
        levelmax = lvl;
        best = node;
    }
    for(auto x : gr[node]) if(!viz[x]) dfs(x, lvl+1);
    viz[node] = false;
}
int main(){
    int n;
    f >> n;
    for(int i = 1; i <n; ++ i){
        int a, b;
        f >> a >> b;
        gr[a].push_back(b);
        gr[b].push_back(a);
    }

    dfs(1, 1);
    levelmax = -1;
    dfs(best, 1);

    g << levelmax;
    return 0;
}