京师吼人

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define N 1000010
struct node{
	int deep,dad,l,r;
}tree[N];
int n;
signed main(){
	std::ios::sync_with_stdio(false);
	cout.tie(NULL);
	cin.tie(NULL);
	int n,x,y,m=-0x3f;cin>>n;
	tree[1].deep=0;
	for(int i=1;i<=N;i++){
		tree[i].deep=0;
	}
	for(int i=1;i<=n;i++){
		cin>>x>>y;
		int s=tree[i].deep;
		tree[i].l=x;
		tree[i].r=y;
		if(x!=0)tree[x].dad=i;
		if(y!=0)tree[y].dad=i;
		if(x!=0)tree[x].deep=s+1;
		if(y!=0)tree[y].deep=s+1;
		m=max(m,s+1);
	}
    if(n<=1)cout<<"0 0";
	else cout<<m;
}