#include <bits/stdc++.h>
#define ll long long
#define pb push_back
using namespace std;
vector<vector<int>>adj(100000);
bool vis[100000];
int mxm,ans;
void dfs(int nod, int d){
    if(d > mxm) {
        ans = nod;
        mxm = d;
    }
    vis[nod] = 1;
    for(auto v : adj[nod]){
        if(!vis[v]) dfs(v,d+1);
    }
    
}
int main()
{   
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    int n,m;
    cin >> n;
    m = n-1;
    for(int i =0;i<m;i++){
        int a,b;
        cin >> a >> b;
        a--;
        b--;
        adj[a].pb(b);
        adj[b].pb(a);
    }
    dfs(0,1);
    memset(vis,0,sizeof(vis));
    dfs(ans,1);
    cout<<mxm;
    
  
    
    
    


    return 0;
}