#include <fstream>
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <string.h>
#include <queue>
#include <math.h>
#include <set>
#include <stack>

#define min(a,b) ((a<b)?a:b)
#define max(a,b) ((a<b)?b:a)
#define abs(a) ((a<0)?-a:a)
#define REP(i,a,b) \
	for (int i=a; i<=b; i++)

#define INF 10000000000001

using namespace std;

//#define TEST
#ifdef TEST
ifstream fin("input.txt");
ofstream fout("output.txt");
#else
ifstream fin("darb.in");
ofstream fout("darb.out");
#endif // TEST

#define MAXN 2000000001
#define pb push_back
#define mp make_pair
#define MOD 1000000007

typedef long long ll;
typedef pair<int,int> pp;

int n;
vector<int> E[100000];

int m=0;
int rez=0;

void DFS(int x, int f, int l)
{
    for (int i=0; i<E[x].size(); i++)
        if (E[x][i]!=f)
            DFS(E[x][i],x,l+1);
    if (l>rez)
    {
        m=x;
        rez=l;
    }
}

int main()
{
    fin>>n;

    for (int i=0; i<n-1; i++)
    {
        int x,y;
        fin>>x>>y;
        E[x-1].push_back(y-1);
        E[y-1].push_back(x-1);
    }

    DFS(m,-1,0);
    rez=0;
    DFS(m,-1,0);

    fout<<rez+1;

	return 0;
}