#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>

using namespace std;

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

vector <int> v[100010];
int n,last,dist[100010];

void dfs(int nod){
    bitset <100010> vaz;
    vector <int> stack;
    stack.push_back(nod);
    vaz[nod]=true;
    dist[nod]=1;
    while (!stack.empty()){
        int current=stack.back();
        if (dist[current]>dist[last]) last=current;
        stack.pop_back();
        for (auto i:v[current])
            if (!vaz[i])
                vaz[i]=true,
                stack.push_back(i),
                dist[i]=1+dist[current];
    }
}

int main()
{
    f>>n;
    for (int x,y,i=1;i<n;++i)
        f>>x>>y,
        v[x].push_back(y),
        v[y].push_back(x);
    dfs(1);
    dfs(last);
    t<<dist[last];
    return 0;
}