#include <stdio.h>
#include <vector>
bool vis[100001];
std::vector<int> adj[100001];
int n,nodf,countf;
void dfs(int nod,int counter)
{
    vis[nod]=1;
    std::vector<int>::iterator it;
    for(it=adj[nod].begin();it!=adj[nod].end();++it)
    {
        if(vis[*it]==0) dfs(*it,counter+1);
    }
    vis[nod]=0;
    if(countf<counter)
    {
        countf=counter;
        nodf=nod;
    }
}
int main()
{
    freopen ("darb.in","r",stdin);
    freopen ("darb.out","w",stdout);
    scanf("%d",&n);
    int a,b;
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&a,&b);
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    dfs(1,1);
    int nodx=nodf;
    //printf("%d\n",nodx);
    countf=0;
    dfs(nodx,1);
    printf("%d\n",countf);
    //printf("%d\n",nodf);
}