#include <bits/stdc++.h>
#define NMAX 100005
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
int n, i, maxx, tmp;
vector <int> g[NMAX];
bool vis[NMAX];
void dfs(int k, int lg)
{
    if(lg > maxx)
    {
        maxx = lg;
        tmp = k;
    }
    vis[k] = 1;
    for(int i = 0; i < g[k].size(); ++ i)
        if(vis[g[k][i]] == 0) dfs(g[k][i], lg + 1);
}
int main()
{
    fin >> n;
    for(i = 1; i < n; ++ i)
    {
        int x, y;
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1, 1);
    memset(vis, 0, sizeof(vis));
    dfs(tmp, 1);
    fout << maxx;
    return 0;
}