#include <cstdio>
#include <vector>
#include <deque>
#include <cstring>
#define N_MAX 100005
#define pb push_back
using namespace std;

vector <int> G[N_MAX];
deque <int> Q;
bool inqueue[N_MAX];
int cnt[N_MAX], last, D, N, K;

void bfs(int random)
{

    memset(cnt,0,sizeof(cnt));
    memset(inqueue,0,sizeof(inqueue));
    Q.pb(random);
    cnt[random] = inqueue[random] = 1;
    vector <int> :: iterator it;
    while(!Q.empty())
    {
        int node = Q.front();
        Q.pop_front();
        for(it = G[node].begin(); it != G[node].end(); it++)
            if(!inqueue[*it])
            {
                Q.pb(*it);
                inqueue[*it] = 1;
                cnt[*it] = cnt[node] + 1;
                D = cnt[*it];
                last = *it;
            }
    }
}
void read()
{
    freopen("darb.in", "r", stdin);
    freopen("darb.out", "w", stdout);
    scanf("%d", &N);
    for(int i = 0; i<N-1; i++)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        G[x].pb(y);
        G[y].pb(x);
    }
}
int main()
{
    read();
    bfs(1);
    bfs(last);
    printf("%d", D);
    return 0;
}