#include<cstdio>
#include<vector>
#include<cstring>
using namespace std;
FILE*in=fopen("darb.in","r");
FILE*out=fopen("darb.out","w");
const int NMAX=100006;
int n,i,maxx,josnod,x,y;
bool b[NMAX];
int dep[NMAX];
vector<int> v[NMAX];
void dfs(int nod)
{
    b[nod]=1;
    for(auto t:v[nod])
    {
        if(b[t]==0)
        {
            dep[t]=dep[nod]+1;
            if(maxx<dep[t])
            {
                maxx=dep[t];
                josnod=t;
            }
            dfs(t);
        }
    }
}
int main()
{
    fscanf(in,"%d",&n);
    for(i=1;i<=n;i++)
    {
        fscanf(in,"%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dep[1]=1;
    dfs(1);
    memset(b,0,sizeof(b));
    memset(dep,0,sizeof(dep));
    maxx=0;
    dep[josnod]=1;
    dfs(josnod);
    fprintf(out,"%d",maxx);
}