#include <bits/stdc++.h>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector<int>v[1000001];
bool viz[1000001];
int n,x,y,sol;
void dfs(int k, int dist)
{
    sol=max(sol,dist);
    viz[k]=1;
    for(int i=0;i<v[k].size();++i)
        if(viz[v[k][i]]==0) dfs(v[k][i], dist+1);
    viz[k]=0;
}
int main()
{
    fin>>n;
    while(fin>>x>>y)
    {
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i=1;i<=n;++i)
        dfs(i, 0);
    fout<<sol+1;
    return 0;
}