#include <bits/stdc++.h>

using namespace std;

int n,m,v[100005],mxm=1,x,y;
vector <int> a[100005];

void DFS(int nod, int val){
    v[nod]=val;
    if(val>v[mxm]) mxm=nod;
    for(int i=0;i<a[nod].size();i++){
        if(!v[a[nod][i]]) DFS(a[nod][i],val+1);
    }
}

int main()
{
    ifstream in("darb.in");
    ofstream out("darb.out");
    in >> n;
    for(int i=1;i<n;i++){
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    DFS(1,0);
    for(int i=1;i<=n;i++) v[i]=0;
    DFS(mxm,0);
    out << v[mxm]+1;
}