#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <queue>
#include <vector>

#define DEBUG 0

using namespace std;

long int dist[10010];

// returns the last element
int bfs ( vector<int> node[] , int n , int start ) {

    int visited[n+1];

    for ( int i = 0 ; i < n+1 ; i++ )
        visited[i] = 0;

    visited[0] = 1;

    queue<int> q;
    q.push(start);

    visited[start] = 1;
    dist[start] = 0;

    while ( !q.empty() ) {
        int parent = q.front();
        q.pop();

        for ( vector<int>::iterator itr = node[parent].begin() ; itr != node[parent].end() ; itr++ ) {
            int child = *itr;

            if ( visited[child] == 1 )
                continue;

            dist[child] = 1 + dist[parent];

            visited[child] = 1;
            q.push(child);
        }
    }

    long int max = -1;
    int last = 1;
    for ( int i = 0 ; i < n+1 ; i++ ) {
        if ( dist[i] > max ) {
            max = dist[i];
            last = i;
        }
    }

    return last;
}

int main ( int argc ,char * argv[] ) {

    int n;
    scanf("%d" , &n );

    vector<int> node[n+1];

    for ( int i = 0 ; i < n-1 ; i++ ) {
        int u,v;
        scanf("%d%d" , &u,&v);
        node[u].push_back(v);
        node[v].push_back(u);
    }

    #if DEBUG
        printf("Adjecency List\n");
        for ( int i = 0 ; i < n+1 ; i++ ) {
            printf("Node %d : " , i);
            for ( vector<int>::iterator itr = node[i].begin() ; itr != node[i].end() ; itr++ ) {
                printf("%d " , *itr);
            }
            printf("\n");
        }
    #endif

    for ( int i = 0 ; i < n+1 ; i++ )
        dist[i] = 0;

    int last_node = bfs( node , n , 1 );

    #if DEBUG
        printf("Last node after 1st BFS : %d\n" , last_node);
    #endif

    for ( int i = 0 ; i < n+1 ; i++ )
        dist[i] = 0;

    last_node = bfs(node , n , last_node );

    #if DEBUG
        printf("Last node after 2nd BFS : %d\n" , last_node);
    #endif

    printf("%ld\n" ,  dist[last_node]);

    return 0;
}