#include <bits/stdc++.h>
#define NM 100005
using namespace std;
ifstream fin ("darb.in");
ofstream fout ("darb.out");
void read();
int n, d1[NM], d2[NM];
vector<int> v[NM];
void dfs1(int nod)
{
    for(auto it:v[nod])
        if(!d1[it])
        {
            d1[it] = d1[nod] + 1;
            dfs1(it);
        }
}
void dfs2(int nod)
{
    for(auto it:v[nod])
        if(!d2[it])
        {
            d2[it] = d2[nod] + 1;
            dfs2(it);
        }
}
int main()
{
    read();
    dfs1(1);
    int maxx = d1[1], nod = 1;
    for(int i=2; i<=n; ++i)
        if(d1[i] > maxx)
        {
            maxx = d1[i];
            nod = i;
        }
    dfs2(nod);
    maxx = 0;
    for(int i=1; i<=n; i++)
        maxx = max(maxx, d2[i]);
    fout << maxx+1;
    return 0;
}
void read()
{
    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);
    }
}