#include <bits/stdc++.h>

using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
const int nMax = 100005;
vector <int> G[nMax];
int dp[nMax], start;
inline void Dfs(int nod) {
    if(dp[start] < dp[nod]){
        start = nod;
    }
    for(const auto &v : G[nod]) {
        if(!dp[v]) {
            dp[v] = dp[nod] + 1;
            Dfs(v);
        }
    }
}
int main()
{
    int n, x, y;
    f >> n;
    for(int i = 1; i < n; i++) {
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dp[1] = 1;
    Dfs(1);
    for(int i = 1; i <= n; i++) {
        dp[i] = 0;
    }
    dp[start] = 1;
    Dfs(start);
    g << dp[start] << "\n";
    return 0;
}