#include <fstream>
#include <vector>

using namespace std;
ifstream cin("darb.in");
ofstream cout("darb.out");
vector<int>v[100005];
int max1=0,ndmx;
void dfs(int nd,int lst,int ad)
{
    for(auto i:v[nd])
    {
        if(i!=lst)
            dfs(i,nd,ad+1);
    }
    if(ad>max1)
    {
        max1=ad;
        ndmx=nd;
    }
}
int main()
{
    int n,a,b;
    cin>>n;
    for(int i=1;i<n;i++)
    {
        cin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1,1,1);
    max1=0;
    dfs(ndmx,ndmx,1);
    cout<<max1;
    return 0;
}