#include <fstream>
#include<vector>
#include<queue>
using namespace std;

ifstream in("darb.in");
ofstream out("darb.out");
int n,viz[100001],last;
vector<int>a[100001];
queue<int>q;

void bfs(int nod){
    int i;
    for(i=1;i<=n;i++)
        viz[i]=0;
    q.push(nod);
    viz[nod]=1;
    int x;
    while(!q.empty()){
        x=q.front();
        for(i=0;i<a[x].size();i++){
            if(viz[a[x][i]]==0){
                q.push(a[x][i]);
                viz[a[x][i]]=viz[x]+1;
                last=a[x][i];
            }
        }
        q.pop();
    }
}

int main()
{
    in>>n;
    int i,x,y;
    for(i=1;i<n;i++){
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    bfs(1);
    bfs(last);
    out<<viz[last];
    return 0;
}