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

using namespace std;

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

int n,maxim,nodm;

vector <pair <int,int> > vecini[100005];

void dfs1(int nod, int cost) {
    int i;
    if(cost > maxim) {
        maxim = cost;
        nodm = nod;
    }
    for(i = 0 ; i < vecini[nod].size(); ++i) {
        if(vecini[nod][i].first) dfs1(vecini[nod][i].first,cost+1);
    }
}

void dfs2(int nod, int cost) {
    int i;
    if(cost > maxim) {
        maxim = cost;
    }
    for(i = 0; i < vecini[nod].size(); ++i) {
        if(vecini[nod][i].second) dfs2(vecini[nod][i].second,cost+1);
    }
}
int main() {
    int i,x,y;
    f>>n;
    for(i = 1 ; i < n; ++i) {
        f>>x>>y;
        vecini[x].push_back({y,0});
        vecini[y].push_back({0,x});
    }
    dfs1(1,1);
    dfs2(nodm,1);
    g<<maxim;
    return 0;
}