#include <bits/stdc++.h>
#define NM 100010
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector <int> v[NM];
int viz[NM],x,y,i,n,nivm,nodm,m;
void dfs(int nod, int nivel)
{
    for(auto it:v[nod])
        if(viz[it]==0)
        {
            viz[it]=viz[nod]+1;
            dfs(it,nivel+1);
        }
    if(nivel>nivm)
    {
        nivm=nivel;
        nodm=nod;
    }
}
int main()
{
    fin>>n;
    for(i=1;i<=n-1;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    viz[1]=1;
    dfs(1,0);
    memset(viz,0,sizeof(viz));
    viz[nodm]=1;
    dfs(nodm,0);
    for(i=1;i<=n;i++)
        if(viz[i]>m)
            m=viz[i];
    fout<<m;
    return 0;
}