#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
const int nmax=100005;
vector<int>v[nmax];
int d[nmax],mx[nmax];
int maxim,n,i,x,y;
void dfs(int x)
{
    int it;
    for(int i=0;i<v[x].size();i++)
    {
        it=v[x][i];
        if(!d[it])
        {
            d[it]=d[x]+1;
            dfs(it);
            if(mx[x]+mx[it]-(2*d[x]-1)>maxim)
                maxim=mx[x]+mx[it]-(2*d[x]-1);
            if(mx[it]>mx[x])
                mx[x]=mx[it];
        }
    }
    if(d[x]>mx[x])
        mx[x]=d[x];
}
int main()
{
    ifstream f("darb.in");
    ofstream g("darb.out");
    f>>n;
    for(i=1;i<=n-1;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    d[1]=1;
    dfs(1);
    if(mx[1]>maxim)
        maxim=mx[1];
    g<<maxim;
    return 0;
}