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

#define NMAX 100001

int n,d[NMAX],maxd=1;
vector<int>g[NMAX];
void dfs(int nod,int par){
    d[nod]=d[par]+1;
    if(d[maxd]<d[nod])maxd=nod;
    for(const auto&son:g[nod]){
        if(son==par)continue;
        dfs(son,nod);
    }
}
signed main(){
#ifndef LOCAL
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
#endif // LOCAL
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    cin>>n;
    for(int i=1;i<n;++i){
        int x,y;
        cin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1,0);
    dfs(maxd,0);
    cout<<d[maxd];
    return 0;
}