#include <bits/stdc++.h>

#define NMax 100005

using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

int N,lenght,lastNode;
vector<int> G[NMax];

void DFS(int node,int father,int level) {
    if(level>lenght)
        lenght=level, lastNode=node;
    for(vector<int>::iterator it=G[node].begin();it!=G[node].end();it++)
        if(*it!= father)
            DFS(*it, node, level + 1);
}

int main()
{
    fin>>N;
    for(int i=1;i<N;i++) {
        int x, y;
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    lenght=0; DFS(1,0,1);
    lenght=0; DFS(lastNode,0,1);
    fout<<lenght;

    return 0;
}