// 100 Puncte
#include <bits/stdc++.h>

using namespace std;

ifstream fin ("darb.in");
ofstream fout ("darb.out");

vector <int> g[100005];
int deepest_node = 0, maxi_level = -1;
int diametru = -1;
bool visited1[100005], visited2[100005];

void dfs (int nod, int level) {
    visited1[nod] = 1;
    if (level>maxi_level) {
        deepest_node = nod;
        maxi_level = level;
    }
    for (int vecin : g[nod]) {
        if (!visited1[vecin]) {
            dfs(vecin, level+1);
        }
    }
}

void dfs2 (int nod, int level) {
    visited2[nod] = 1;
    diametru = max (diametru, level);
    for (int vecin : g[nod]) {
        if (!visited2[vecin]) {
            dfs2(vecin, level+1);
        }
    }
}

int main()
{
    fin.tie(0); fin.sync_with_stdio(false);
    int n, x, y; fin>>n;
    for (int i=1; i<n; i++) {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    /* Mergem pana la cea mai indepartata frunza, dupa din frunza aia mergem pana la cea mai indepartata
    fruznza, iar distanta dintre ele este diametrul arborelui */
    dfs(1, 1);
    dfs2(deepest_node, 1);
    fout<<diametru;
    return 0;
}