#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

int n,maxim,nodm;

vector <int> vecini[100005];

bool viz[100005];

void dfs(int nod, int cost) {
    int i;
    viz[nod] = 1;
    if(cost > maxim) {
        maxim = cost;
        nodm = nod;
    }
    for(i = 0 ; i < vecini[nod].size(); ++i) {
        if(!viz[vecini[nod][i]]) dfs(vecini[nod][i],cost+1);
    }
}

int main() {
    int i,x,y;
    f>>n;
    for(i = 1 ; i < n; ++i) {
        f>>x>>y;
        vecini[x].push_back(y);
        vecini[y].push_back(x);
    }
    dfs(1,1);
    for(i = 1; i <= n; ++i) {
        viz[i] = 0;
    }
    dfs(nodm,1);
    g<<maxim;
    return 0;
}