#include<fstream>
#include<vector>
#include<cstring>
#define N 100100
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int i,n,x,y,maxi,care,d[N];
vector<int>v[N];
inline void dfs(int x,int t)
{
    d[x]=d[t]+1;
    for(vector<int>::iterator it=v[x].begin();it!=v[x].end();++it)
    if(*it!=t)
    {
        dfs(*it,x);
    }
}
int main()
{
    f>>n;
    for(i=1;i<n;++i)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0);
    for(i=1;i<=n;++i)
    if(d[i]>maxi)
    care=i,maxi=d[i];
    memset(d,0,sizeof(d));
    dfs(care,0);
    maxi=0;
    for(i=1;i<=n;++i)
    if(d[i]>maxi)
    maxi=d[i];
    g<<maxi<<'\n';
    return 0;
}