#include <fstream>
#include <vector>
#define NMAX 100000

using namespace std;

ifstream cin("darb.in");
ofstream cout("darb.out");

int viz[NMAX+1], l, n, maxi, last;
vector <int> v[NMAX+1];

void read()
{
    int n1,n2;
    cin>>n;
    for (int i=1; i<=n; i++)
    {
        cin>>n1>>n2;
        v[n1].push_back(n2);
        v[n2].push_back(n1);
    }
}
void dfs(int nod, int lung)
{
    viz[nod] = 1;
    if (lung>maxi)
        maxi = lung, last = nod;
    for (int i=0; i<v[nod].size(); i++)
        if (!viz[v[nod][i]])
        {
            dfs(v[nod][i], lung+1);

        }
    viz[nod] = 0;
}


int main()
{
    read();
    dfs(1, 0);
    dfs(last, 0);
    cout<< maxi + 1;
}