#include<cstdio>
#include<vector>
using namespace std;
int n,viz[100005],p,lmax;
vector<int>v[100005];
void citire()
{
    int x,y;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }

}
void dfs(int x,int lvl)
{
    if(lvl>lmax)
    {
        lmax=lvl;
        p=x;
    }
    viz[x]=1;
    for(int i=0;i<v[x].size();i++)
    {
        if(viz[v[x][i]]==0)
            dfs(v[x][i],lvl+1);
    }
}
int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);

    citire();
    dfs(1,1);
    for(int i=1;i<=n;i++)
        viz[i]=0;
    lmax=0;
    dfs(p,1);
    printf("%d\n",lmax);
    return 0;
}