#include <iostream>
#include <cstdio>
#include <vector>
#include <bitset>
#define MAXN 100100

using namespace std;

vector<int> graf[MAXN];
int n, m;
bitset<MAXN> viz;

void citire()
{
	int x, y;
    scanf("%d\n", &n); m = n-1;
    for (int i = 1; i <= m; i++) {
        scanf("%d %d\n", &x, &y);
		graf[x].push_back(y);
		graf[y].push_back(x);
    }
}

pair<int, int> dfs(int nod)
{
    int maxDist = 0, nd = nod;
    viz[nod] = 1;
    for (int i = 0, t = graf[nod].size(); i < t; i++) {
		if (viz[graf[nod][i]]) continue;
		pair<int, int> lenDest = dfs(graf[nod][i]);
		if (lenDest.first > maxDist) {
			maxDist = lenDest.first;
			nd = lenDest.second;
		}
    }
    return make_pair(maxDist+1, nd);
}

int main()
{
    freopen("darb.in", "r", stdin);
    freopen("darb.out", "w", stdout);

	citire();
	int a = dfs(1).second;
	viz = 0;
	int sol = dfs(a).first;
	printf("%d", sol);

    return 0;
}