#include <bits/stdc++.h>

using namespace std;

ifstream in("darb.in");
ofstream out("darb.out");

vector <vector<int>> a;
vector <int> gasit;
int dmax=0,nodmax=1;

void dfs(int nod,int d)
{
    if(dmax<d)
    {
        dmax=d;
        nodmax=nod;
    }
    for(int x : a[nod])
    {
        if(!gasit[x])
        {
            gasit[x]=1;
            dfs(x,d+1);
        }
    }
}
int main()
{
    int n;
    in>>n;
    a.resize(n+1);
    gasit.resize(n+1);
    for(int i=1;i<=n-1;i++)
    {
        int x,y;
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    gasit[1]=1;
    dfs(1,0);
    for(int i=1;i<=n;i++)
    {
        gasit[i]=0;
    }
    dfs(nodmax,0);
    out<<dmax+1;
    return 0;
}