#include <cstdio>
#include <cstring>
#include <vector>
#define MAXN 100001
using namespace std;
vector <int> v[MAXN];
int st,maxim;
bool viz[MAXN];
void dfs(int nod,int dist)
{
    viz[nod]=true;
    if(dist>maxim)
        maxim=dist,st=nod;
    for(unsigned int i=0;i<v[nod].size();i++)
        if(!viz[v[nod][i]])
            dfs(v[nod][i],dist+1);
}
int main()
{
    FILE *fin,*fout;
    fin=fopen("darb.in","r");
    fout=fopen("darb.out","w");
    int n,x,y;
    fscanf(fin,"%d",&n);
    for(int i=1;i<n;i++)
    {
        fscanf(fin,"%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,1);
    memset(viz,false,sizeof(viz));dfs(st,1);
    fprintf(fout,"%d",maxim);
    fclose(fin);
    fclose(fout);
    return 0;
}