#include <cstdio>
#include <vector>
#include <queue>
#include <cstring>
#define SIZE 100002
using namespace std;

vector <int> adj[SIZE];
queue <int> q;
int n, MAX, MAX_node, dist_min[SIZE];

inline void read();
inline void solve();
inline void write();

int main()
{
    read();
    solve();
    write();
    return 0;
}

inline void read()
{
    freopen("darb.in", "r", stdin);
    scanf("%d", &n);
    for(int i = 1; i <= n - 1; ++i)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
}

inline void BFS(int source)
{
    memset(dist_min, 0x3f3f3f3f, sizeof(dist_min));
    q.push(source);
    dist_min[source] = 0;
    while( !q.empty() )
    {
        int node = q.front();
        q.pop();

        for( vector <int> :: iterator it = adj[node].begin(); it != adj[node].end(); ++it)
            if( dist_min[*it] > dist_min[node] + 1)
            {
                dist_min[*it] = dist_min[node] + 1;
                q.push(*it);

                if( dist_min[*it] > MAX)
                {
                    MAX = dist_min[*it];
                    MAX_node = *it;
                }
            }
    }
}

inline void solve()
{
    BFS(1);
    BFS(MAX_node);
}

inline void write()
{
    freopen("darb.out", "w", stdout);
    printf("%d\n", MAX + 1);
}