#include <iostream>
#include <fstream>
#include <cstdio>
#include <cstring>
#include <vector>

using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");

#define ll long long
#define ull unsigned long long
#define pb push_back
const int NMax = 1e5 + 5;
const ll inf = 1e18 + 7;

int N,mxDist,mxNode;
vector<int> v[NMax];

void dfs(int node,int dad,int dist) {

    for (int nxt : v[node]) {
        if (nxt == dad) {
            continue;
        }

        dfs(nxt,node,dist+1);
    }

    if (mxDist < dist) {
        mxDist = dist;
        mxNode = node;
    }
}

int main() {
    in>>N;
    for (int i=1;i < N;++i) {
        int x,y;
        in>>x>>y;

        v[x].pb(y);
        v[y].pb(x);
    }

    mxDist = -1,mxNode = -1;
    dfs(1,0,1);

    dfs(mxNode,0,1);

    out<<mxDist<<'\n';

    in.close();out.close();
    return 0;
}