#include <iostream>
#include <cstdio>
#include <vector>
#include <cstring>
using namespace std;

vector <int >g [100005];

int n,drum,v[100005],nod_n;

void citesc()
{
    scanf("%d",&n);
    for (int i=1; i<n; ++i)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
}

void bfs(int nod,int d)
{
    if (drum<d)
    {
        drum=d;
        nod_n=nod;
    }
    for (vector <int > :: iterator it=g[nod].begin(); it!=g[nod].end(); ++it)
        if (!v[*it])
        {
            v[*it]=1;
            bfs(*it,d+1);
            v[*it]=0;
        }
}

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    citesc();
    bfs(1,1);
    memset(v,0,100005);
    bfs(nod_n,1);
    printf("%d",drum);
    return 0;
}