#include <bits/stdc++.h>

using namespace std;

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

int i,x,y,n, viz[100001], m, im;
vector<int>v[100001];

void dfs(int nod)
{
    for (auto i:v[nod])
        if (viz[i]==0)
        {
            viz[i]=viz[nod]+1;
            dfs(i);
        }
}

int main()
{
    fin>>n;
    for (i=1;i<n;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    viz[1]=1;
    dfs(1);
    for (i=1;i<=n;i++)
        if (viz[i]>m)
            {
                m=viz[i];
                im=i;
            }
    memset(viz,0,sizeof(viz));
    m=0;
    viz[im]=1;
    dfs(im);
    for (i=1;i<=n;i++)
        if (viz[i]>m)
            m=viz[i];
    fout<<m;
    return 0;
}