#include <bits/stdc++.h>
using namespace std;ifstream fin("darb.in");ofstream fout("darb.out");int n;vector<int>lista[100005];int D[100005];void read(){fin>>n;int x,y;for(int i=1;i<n;i++){fin>>x>>y;lista[x].push_back(y);lista[y].push_back(x);}}void dfs(int nod,int dist,int D[]){if(D[nod]!=-1)return;D[nod]=dist;for(auto x:lista[nod])dfs(x,dist+1,D);}void init(){for(int i=1;i<=n;i++) D[i]=-1;}int main(){read();init();dfs(1,1,D);int x=1;for(int i=2;i<=n;i++)if(D[i]>D[x])x=i;init();dfs(x,1,D);int sol=D[1];for(int i=2;i<=n;i++){if(D[i]>sol)sol=D[i];}fout<<sol;return 0;}