#include <fstream>
#include <vector>
#include <queue>
#include <cstring>
using namespace std;

ifstream cin ("darb.in");
ofstream cout ("darb.out");

long long int t,n,i,j,d,k,m,x,y,a[1000001],b[1000001],dp[10][100],start,capat,len,sum,ok,l,r,mini,c,ans,nr,maxi;
const int MOD=1e9+7;
char v[505][505];
char s[200005];
vector<int>nod[1000001];
queue<int>q;

void bfs(int start)
{
    memset(a,0,sizeof(a));
    memset(b,0,sizeof(b));
    q.push(start);
    a[start]=1;
    b[start]=1;
    while(!q.empty())
    {
        k=q.front();
        for(i=0;i<nod[k].size();i++)
        {
            if(b[nod[k][i]]==0)
            {
                q.push(nod[k][i]);
                a[nod[k][i]]=a[k]+1;
                b[nod[k][i]]=1;
                len=a[nod[k][i]];
                capat=nod[k][i];
            }
        }
        q.pop();
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin>>n;
    for(i=1;i<n;i++)
    {
        cin>>x>>y;
        nod[x].push_back(y);
        nod[y].push_back(x);
    }
    bfs(1);
    bfs(capat);
    cout<<len;
    return 0;
}