#include<bits/stdc++.h>

using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
int niv[100004], n, viz[100004];
vector <int> L[100004];
queue<int> q;
void BFS(int k)
{
	q.push(k);
	viz[k] = 1;
	niv[k] = 1;
	while (!q.empty())
	{
		k = q.front();
		q.pop();
		for (auto i : L[k])
			if (viz[i] == 0)
			{
				q.push(i);
				viz[i] = 1;
				niv[i] = 1 + niv[k];
            }
    }
}


int main()
{
    int x,y,i;
	fin >> n;
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    sort(L[i].begin(), L[i].end());
    BFS(1);
    int nivmax=0,p=0;
    for(i=1;i<=n;i++)
        if(nivmax<niv[i])
    {
        nivmax=niv[i];
        p=i;
    }
    nivmax=0;
    for(i=1;i<=n;i++)
    {
        viz[i]=0;
        niv[i]=0;
    }
    BFS(p);
    for(i=1;i<=n;i++)
        if(nivmax<niv[i])
        nivmax=niv[i];
    fout<<nivmax;
    return 0;
}