#include <bits/stdc++.h>
using namespace std;ifstream f ("darb.in");ofstream g ("darb.out");int n,m,x,y,t,sol,viz[100003];vector <int> v[100003];void dfs(int x,int l){viz[x]=t;if(l>sol) sol=l,y=x;for(int j=0;j<v[x].size();++j) if(viz[v[x][j]]!=t) dfs(v[x][j],l+1);}int main(){f>>n;for(int i=1;i<n;++i){f>>x>>y;v[x].push_back(y);v[y].push_back(x);}t=1,dfs(1,1);t=2,dfs(y,1);g<<sol;return 0;}