#include <bits/stdc++.h>
#define nmax 100005
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int n,nod_max=-1,dist=0;
vector<int> adj[nmax];
void dfs(int nod,int tata,int d)
{
    if(d>dist)
    {
        dist=d;
        nod_max=nod;
    }
    for(auto it:adj[nod])
    {
        if(it==tata) continue;
        dfs(it,nod,d+1);
    }
}
int main()
{
    f>>n;
    for(int i=1;i<n;i++)
    {
        int a,b;
        f>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    dfs(1,0,0);
    int A=nod_max;
    int dist1=dist;
    dist=0;
    nod_max=-1;
    dfs(A,0,0);
    g<<dist+1;
}