#include<cstdio>
#include<vector>
using namespace std;
int n,a,b,maxim,nodul;
bool viz[100001];
vector<int>v[100001];

void dfs(int nod,int dist){
    viz[nod]=true;
    if(dist>maxim){
        maxim=dist;
        nodul=nod;
    }
    for(int i=0;i<v[nod].size();i++)
        if(viz[v[nod][i]]==false)
            dfs(v[nod][i],dist+1);
}

int main(){
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    for(int i=1;i<=n-1;i++){
        scanf("%d%d",&a,&b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1,0);
    for(int i=1;i<=n;i++)
        viz[i]=false;
    dfs(nodul,0);
    printf("%d",maxim+1);
    return 0;
}