#include <bits/stdc++.h>
using namespace std;
///------------------
ifstream in("darb.in");
ofstream out("darb.out");
///------------------
int dist[100005],n,r,ma;
vector <int> v[100005];
///------------------
void dfs(int nod,int par)
{
    for(auto it:v[nod])
        if(it!=par)
        {
            dist[it]=dist[nod]+1;
            dfs(it,nod);
        }
    if(dist[nod]>ma)
    {
        ma=dist[nod];
           r=nod;
    }
}
///------------------
int main()
{
    in>>n;
    for(int i=1; i<n; ++i)
    {
        int x,y;
        in>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0);
    ma = 0;
    for(int i=1; i<=n; ++i)
    {
        dist[i] = 0;
    }
    dfs(r,0);
    out<<ma + 1;
}