#include<bits/stdc++.h> using namespace std; int a[110]; int main(){ int x; cin>>x; a[1]=1; int m,n,min=-1; for(int i=1;i<=x;i++){ cin>>m>>n; a[m]=a[i]+1; a[n]=a[i]+1; min=max(max(min,a[m]),a[n]); } cout<<min-1<<endl; }