#include <cstdio>
#include <vector>
#include <queue>

using namespace std;
#define MAX 100005

vector<int> v[MAX];
queue<int> q;

int viz[MAX], n;
void bfs(int nod);

int main()
{
    freopen("darb.in", "r", stdin);
    freopen("darb.out", "w", stdout);
    int a, b, i;
    scanf("%d", &n);
    for(i=1; i<n; i++)
    {
        scanf("%d%d", &a, &b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    bfs(1); //plecam dintr-un nod aleatoriu
    int ultnod = 1;
    for(i=2; i<=n; i++)
        if(viz[ultnod] < viz[i])
            ultnod = i;
    bfs(ultnod); //facem a doua parcurgere din ultimul nod accesat
    int sol = 0;
    for(i=1; i<=n; i++)
        if(sol < viz[i])
            sol = viz[i];
    printf("%d\n", sol);
    return 0;
}
void bfs(int nod)
{
    int tata, fiu, i;
    while(!q.empty()) q.pop();
    for(i=1; i<=n; i++) viz[i] = 0;
    q.push(nod);
    viz[nod] = 1;
    while(!q.empty())
    {
        tata = q.front();
        q.pop();
        vector<int>::iterator it;
        for(it = v[tata].begin(); it != v[tata].end(); ++it)
        {
            fiu = *it;
            if(!viz[fiu])
            {
                viz[fiu] = viz[tata] + 1;
                q.push(fiu);
            }
        }
    }
}