#include <cstdio>
#include <vector>
#include <cstring>

using namespace std;

#define MAX_N 100000

vector< int > v[MAX_N];
bool marked[MAX_N];
int leaf, ans;

void read( FILE *fin, int &n ) {
    fscanf( fin, "%d", &n );
    for ( int i = 1; i < n; ++i ) {
        int x, y;
        fscanf( fin, "%d%d", &x, &y );

        v[x].push_back( y );
        v[y].push_back( x );
    }
}

void dfs( int node, int dist ) {
    if ( dist > ans ) {
        leaf = node;
        ans = dist;
    }
    marked[node] = true;
    for ( vector< int >::iterator it = v[node].begin(); it != v[node].end(); ++it )
        if ( !marked[*it] )
            dfs( *it, dist + 1 );
}

int main() {
    FILE *fin, *fout;

    fin = fopen( "darb.in", "r" );
    int n;
    read( fin, n );
    fclose( fin );

    dfs( 1, 0 );
    memset( marked, false, sizeof( marked ) );
    ans = 0;
    dfs( leaf, 0 );

    fout = fopen( "darb.out", "w" );
    fprintf( fout, "%d\n", ans + 1 );
    fclose( fout );
}