#include<cstdio> #include<cstring> #include<queue> #include<iostream> using namespace std; struct Edge{ int ls,rs; }; int mx; Edge e[1000005]; void dfs(int u,int depth){ mx=max(depth,mx); if(e[u].ls !=0) dfs(e[u].ls,depth+1); if(e[u].rs !=0) dfs(e[u].rs,depth+1); } int main(){ int n; scanf("%d",&n); for(int i=1;i<=n;i++){ scanf("%d %d",&e[i].ls,&e[i].rs); } dfs(1,1); printf("%d\n",mx); return 0; }