#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

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

#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define pb push_back
#define mp make_pair
const int NMax = 1e5 + 5;
const int inf = 1e9 + 5;
using zint = short;

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

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

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

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

    if (mxDist < depth) {
        mxDist = depth;
        lowestLeaf = 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);
    }

    dfs(1,0,0);
    int root = lowestLeaf;
    mxDist = 0;
    dfs(root,0,0);

    out<<mxDist + 1<<'\n';

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