import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); while (in.hasNext()) { int n = in.nextInt(); int[] p = new int[n]; int[] l = new int[n]; int[] r = new int[n]; int root=0; for(int i=0;i<n;i++){ p[i]=-1; l[i]=-1; r[i]=-1; } for(int i=0;i<n-1;i++){ int tmpp = in.nextInt(); int tmpc = in.nextInt(); p[tmpc]=tmpp; if(l[tmpp]==-1)l[tmpp]=tmpc; else r[tmpp]=tmpc; } for(int i=0;i<n;i++){ if(p[i]==-1){ root=i; break; } } System.out.println(result(root,l,r)); } in.close(); } private static int result(int start, int[] l, int[] r){ if(l[start]==-1&&r[start]==-1)return 1; if(l[start]==-1&&r[start]!=-1)return 1+result(r[start],l,r); if(r[start]==-1&&l[start]!=-1)return 1+result(l[start],l,r); else return Math.max(1+result(r[start],l,r), 1+result(l[start],l,r)); } }