#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
const int NMAX = 100005;
vector <int> vec[NMAX];
int dist[NMAX];
void dfs(int u, int f) {
    for(int v : vec[u]) {
        if(v != f) {
            dist[v] = dist[u] + 1;
            dfs(v, u);
        }
    }
}

int main() {
    int n;
    freopen("darb.in", "r", stdin);
    freopen("darb.out", "w", stdout);
    scanf("%d", &n);
    for(int i = 1; i < n; i++) {
        int x, y;
        scanf("%d%d", &x, &y);
        vec[x].push_back(y);
        vec[y].push_back(x);
    }
    dfs(1, 0);
    int poz = 2;
    for(int i = 1; i <= n; i++) {
        if(dist[poz] < dist[i]) {
            poz = i;
        }
    }
    for(int i = 1; i <= n; i++) {
        dist[i] = 0;
    }
    dfs(poz, 0);
    int maxim = 0;
    for(int i = 1; i <= n; i++) {
        maxim = max(maxim, dist[i]);
    }
    printf("%d\n", maxim + 1);
    return 0;
}