#include<cstdio>
#include<fstream>
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<vector>
#include<bitset>
#include<deque>
#include<queue>
#include<set>
#include<map>
#include<cmath>
#include<cstring>
#include<ctime>
#include<cstdlib>
#include<unordered_map>

#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<ll,ll>

using namespace std;

const int nmax = 100005;
const int inf = (1LL << 31) - 1;

int n, i, x, y, d[nmax], maxi, node;

vector<int> v[nmax];
deque<int> q;

void bfs(int source)
{
    memset(d, 0, sizeof(d));

    q.pb(source);
    d[source] = 1;

    while(!q.empty())
    {
        x = q.front();
        q.pop_front();

        for(auto it : v[x])
            if(!d[it])
            {
                d[it] = d[x] + 1;
                q.pb(it);
            }
    }
}

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

    scanf("%d", &n);

    for(i = 1; i < n; i++)
    {
        scanf("%d%d", &x, &y);
        v[x].pb(y);
        v[y].pb(x);
    }

    bfs(1);
    for(i = 1; i <= n; i++)
        if(d[i] > maxi)
        {
            maxi = d[i];
            node = i;
        }

    bfs(node);
    for(i = 1; i <= n; i++)
        maxi = max(maxi, d[i]);

    printf("%d\n", maxi);

    return 0;
}