#include<bits/stdc++.h>
#define fi first
#define sc second
#define ll long long
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int n, dist[100010], x, ans, maxim;
bool viz[100010];
vector<int>v[100010];
void dfs(int nod, int d)
{
    dist[nod]=d;
    viz[nod]=1;
    for(int i=0; i<v[nod].size(); i++)
    {
        if(!viz[v[nod][i]])
            dfs(v[nod][i], d+1);
    }
}
int main()
{
    f>>n;
    for(int i=1; i<=n-1; i++)
    {
        int x, y;
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1, 1);
    for(int i=1; i<=n; i++)
    {
        if(maxim<dist[i])
            maxim=dist[i], x=i;
    }
    memset(viz, 0, sizeof(viz));
    dfs(x, 1);
    for(int i=1; i<=n; i++)
    {
        if(maxim<dist[i])
            maxim=dist[i];
    }
    g<<maxim;
    return 0;
}