#include <bits/stdc++.h>
 
using namespace std;
 
#if 1
    #define pv(x) cout<<#x<<" = "<<(x)<<"; ";cout.flush()
    #define pn cout<<endl
#else
    #define pv(x)
    #define pn
#endif
 
#ifdef INFOARENA
    ifstream in("online.in");
    ofstream out("online.out");
#else
    #define in cin
    #define out cout
#endif
 
using ll = long long;
using ull = unsigned long long;
using uint = unsigned int;
#define pb push_back
#define mp make_pair
const int NMax = 1e5 + 5;
const int MMax = 1e4 + 5;
const ll inf_ll = 1e18 + 5;
const int inf_int = 1e9 + 5;
const int mod = 100003;
using zint = int;

vector<int> adj[NMax];

void dfs(int node, int dad, int depth, int& start, int& len) {
    if (len < depth) {
        len = depth;
        start = node;
    }

    for (int nxt : adj[node]) {
        if (nxt == dad) {
            continue;
        }

        dfs(nxt, node, depth + 1, start, len);
    }
}

int main() {
    cin.sync_with_stdio(false);
    cin.tie(0);
     
    int N;
    in >> N;
    for (int i = 1;i < N; ++i) {
        int x,y;
        in >> x >> y;
        adj[x].pb(y);
        adj[y].pb(x);
    }

    int node, maxLen = 0;
    dfs(1, 0, 1, node, maxLen);
    maxLen = 0;
    dfs(node, 0, 1, node, maxLen);
    out << maxLen << '\n';
 
    return 0;
}