#include <bits/stdc++.h>

using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
const int lim=100100;
int n,i,viz[lim],mx,st;
vector <int> v[lim];
void dfs(int x,int dist)
{
    viz[x]=1;
    if(dist>mx)
    {
        mx=dist;st=x;
    }
    for(auto i:v[x])
    {
        if(viz[i]==0)
        {
            dfs(i,dist+1);
        }
    }
}

int main()
{
    fin>>n;
    for(i=1;i<=n-1;i++)
    {
        int f,s;
        fin>>f>>s;
        v[f].push_back(s);
        v[s].push_back(f);
    }
    dfs(1,0);
    mx=0;
    for(i=1;i<=n;i++)
        viz[i]=0;
    dfs(st,0);
    fout<<mx+1;
    return 0;
}