#include<bits/stdc++.h>

using  namespace std;

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


int n, m, c;
int viz[100001];
int cnt = 1;
vector<vector<int>> nums;
int nmax = 0;
int node = 0;

void dfs(int k)
{
    if(viz[k] > nmax)
    {
        nmax = viz[k];
        node = k;
    }
    for(int x : nums[k])
    {
        if(!viz[x])
        {
            viz[x] = viz[k] + 1;
            dfs(x);
        }
    }
}

int main()
{
    fin >> n ;
    nums.resize(n + 1);
    for(int i = 1; i <= n-1; i++)
    {
        int x, y;
        fin >> x >> y;
        nums[x].push_back(y);
        nums[y].push_back(x);
    }
    viz[1] = 1;
    dfs(1);
    nmax = 0;
    for(int i = 1; i <= n; i++) viz[i] = 0;
    dfs(node);
    fout << nmax + 1;


}