#include<algorithm>
#include<bitset>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
#include<deque>
#include<fstream>
#include<iomanip>
#include<iostream>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<vector>

using namespace std;

#ifdef HOME
const string inputFile = "input.txt";
const string outputFile = "output.txt";
#else
const string problemName = "darb";
const string inputFile = problemName + ".in";
const string outputFile = problemName + ".out";
#endif

const int NMAX = 100000 + 5;

int N, F;
vector<int> V[NMAX];
int lvl[NMAX];
int dad[NMAX];
bitset<NMAX> viz;

void dfs(int x) {
    viz[x] = 1;
    lvl[x] = lvl[dad[x]] + 1;

    for(auto y : V[x])
        if(!viz[y]) {
            dad[y] = x;
            dfs(y);
        }

    if(lvl[x] > lvl[F])
        F = x;
}

int main() {
    int i, x, y;

#ifndef ONLINE_JUDGE
    freopen(inputFile.c_str(), "r", stdin);
    freopen(outputFile.c_str(), "w", stdout);
#endif

    scanf("%d", &N);

    for(i = 1; i <= N - 1; i++) {
        scanf("%d%d", &x, &y);
        V[x].push_back(y);
        V[y].push_back(x);
    }

    dfs(1);
    viz = 0;
    dad[F] = 0;
    dfs(F);

    printf("%d\n", lvl[F]);

    return 0;
}