#include <fstream>
#include <iostream>
#include <vector>
#include <bitset>
#include <string.h>
#include <algorithm>
#include <iomanip>
#include <math.h>
#include <time.h>
#include <stdlib.h>
#include <set>
#include <map>
#include <string>
#include <queue>
#include <deque>

using namespace std;

const char infile[] = "darb.in";
const char outfile[] = "darb.out";

ifstream fin(infile);
ofstream fout(outfile);

const int MAXN = 100005;
const int oo = 0x3f3f3f3f;

typedef vector<int> Graph[MAXN];
typedef vector<int> :: iterator It;

const inline int min(const int &a, const int &b) { if( a > b ) return b;   return a; }
const inline int max(const int &a, const int &b) { if( a < b ) return b;   return a; }
const inline void Get_min(int &a, const int b)    { if( a > b ) a = b; }
const inline void Get_max(int &a, const int b)    { if( a < b ) a = b; }

class Tree {
public:
    Tree(const int &N) {
        this -> N = N;
        this -> G.resize(N);
        this -> level.resize(N);
    }
    void addEdge(const int &x, const int &y) {
        G[x].push_back(y);
        G[y].push_back(x);
    }
    int getDiameter(void) {
        srand(time(NULL));
        return level[dfs(dfs((rand() % N), 0, 1), 0, 1)];
    }
private:
    int dfs(const int &Node, const int &Father, const int &actLevel) {
        level[Node] = actLevel;
        int maxDiamenterNode = Node;
        for(It it = G[Node].begin(), fin = G[Node].end(); it != fin ; ++ it) {
            if(*it != Father) {
                int temp;
                if(level[maxDiamenterNode] < level[(temp = dfs(*it, Node, actLevel + 1))])
                    maxDiamenterNode = temp;
            }
        }
        return maxDiamenterNode;
    }
    int N;
    vector < vector <int> > G;
    vector < int > level;
};

int main() {
    int N;
    fin >> N;
    Tree T(N);
    for(int i = 1 ; i != N ; ++ i) {
        int x, y;
        fin >> x >> y;
        -- x;
        -- y;
        T.addEdge(x, y);
    }
    fout << T.getDiameter() << '\n';
    fin.close();
    fout.close();
    return 0;
}