#include <fstream>
#include <vector>
#include <cstring>

using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

vector<int> V[100001];
int node_max;
bool used[100001];
int diameter;

void dfs(int nod, int deep)
{
    used[nod] = true;
    if(deep > diameter)
    {
        diameter = deep;
        node_max = nod;
    }
    for(vector<int>::iterator it = V[nod].begin(); it!=V[nod].end();it++)
        if(!used[*it])
            dfs(*it,deep+1);
}

int main()
{
    int n;
    fin>>n;
    for(int i=1;i<n;i++)
    {
        int x,y;
        fin>>x>>y;
        V[x].push_back(y);
        V[y].push_back(x);
    }
    dfs(1,0);
    memset(used, false, sizeof(used));
    dfs(node_max,0);
    fout<<diameter+1;





    fin.close();
    fout.close();
    return 0;
}