#include <bits/stdc++.h>
#define NMax 100000
#define oo 1<<30
using namespace std;

vector<int> a[NMax+1];
int COADA[NMax+1];
int d[NMax+1];
int N;

int BFS(int x0, int& xf)
{
    int i,x,y,inc,sf;

    for(i = 1; i <= N; ++i) d[i] = oo;
    d[x0] = inc = sf = 0;
    COADA[0] = x0;
    while(inc <= sf)
    {
        x = COADA[inc++];
        for(i = 0; i < a[x].size(); ++i)
        {
            y = a[x][i];
            if(d[y] == oo){
                d[y] = d[x] + 1;
                COADA[++sf] = y;
            }
        }
    }
    xf = COADA[sf];
    return d[xf];
}

int main(){
    FILE* fin = fopen("darb.in","r");
    FILE* fout = fopen("darb.out","w");

    int i,x,y,xf;

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

    BFS(1,xf);
    fprintf(fout,"%d\n",BFS(xf,x)+1);


return 0;
}