#include <cstdio>
#include <vector>
#include <queue>
using namespace std;

#define Nmax 100002
#define inf 0x3f3f3f3f

FILE *f = fopen ( "darb.in", "r" );
FILE *g = fopen ( "darb.out", "w" );

vector < int > G[Nmax];
queue < int > Q;
int dist[Nmax], N;

int BFS ( int start ){

    vector < int > :: iterator it;

    for ( int i = 1; i <= N; ++i )
        dist[i] = inf;
    dist[start] = 0;

    Q.push ( start );

    while ( !Q.empty() ){
        int nod = Q.front();
        Q.pop();
        for ( it = G[nod].begin(); it < G[nod].end(); ++it )
            if ( dist[*it] > dist[nod] + 1 ){
                dist[*it] = dist[nod] + 1;
                Q.push ( *it );
            }
    }

    int maxx = -1, nod;

    for  ( int i = 1; i <= N; ++i )
        if ( dist[i] != inf && dist[i] > maxx ){
            maxx = dist[i];
            nod = i;
        }
    return nod;
}

int main(){

    int M, x, y, Start;

    fscanf ( f, "%d", &N );

    for ( int i = 1; i < N; ++i ){
        fscanf ( f, "%d%d", &x, &y );
        G[x].push_back ( y );
        G[y].push_back ( x );
    }

    Start = BFS ( 1 );

    fprintf ( g, "%d", dist[BFS ( Start )] + 1 );

    return 0;
}