#include <bits/stdc++.h>

using namespace std;

const int MAXN=1e5;
vector<int> g[MAXN+1];

int maxim, care;
void dfs(int nod, int par, int depth)
{
    if(depth>maxim)
        maxim=depth, care=nod;
    for(auto vecin:g[nod])
        if(vecin!=par)
            dfs(vecin, nod, depth+1);
}
int main()
{
    ifstream cin("darb.in");
    ofstream cout("darb.out");
    int n;
    cin>>n;
    for(int i=1, x, y; i<n; i++)
    {
        cin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1, 0, 1);
    maxim=0;
    dfs(care, 0, 1);
    cout<<maxim;
    return 0;
}