#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");

int n, x, y;
vector < int > v[100005];
int fr_max, d_max;
bool viz[100005];
int d[100005];

int dfs(int nod) {
    if (d[nod] > d_max) {
        fr_max = nod;
        d_max = d[nod];
    }
    viz[nod] = 1;
    for (int vec: v[nod]) {
        if (!viz[vec]) {
            d[vec] = d[nod] + 1;
            dfs(vec);
        }
    }
}

int main() {
    f >> n;
    for (int i=1;i<n;i++) {
        f >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    d[1] = 1;
    dfs(1);
    for (int i=1;i<=n;i++) {
        viz[i] = 0;
        d[i] = 0;
    }
    d[fr_max] = 1;
    d_max = 0;
    dfs(fr_max);
    g << d_max;
    return 0;
}