#include<bits/stdc++.h>
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int n,x,y,k,i,dist,viz[100001],M;
vector <int> G[100001];
void dfs(int nod,int k)
{
    viz[nod]=1;
    if(k>M)
        M=k,dist=nod;
    for(int i=0;i<G[nod].size();++i)
        if(!viz[G[nod][i]])
            dfs(G[nod][i],k+1);
}
int main()
{
    f>>n;
    for(i=1;i<=n;i++)
    {
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1,1);
    for(i=1;i<=n;i++)
        viz[i]=0;
    M=0;
    dfs(dist,1);
    g<<M;
    return 0;
}