C++ :

#include<bits/stdc++.h>
using namespace std;

int n,a[1010][1010],dep[1010],fa[1010],width[1010];
int maxw,maxd;//最大宽度和深度
int u,v; 

void dfs(int x,int fath){
	fa[x] = fath;
	dep[x] = dep[fath] + 1;
	width[dep[x]]++;
	maxd = max(maxd,dep[x]);//最大宽度 
	maxw = max(maxw,width[dep[x]]);//最大深度 
	
	for(int i = 1;i <= n;i++){
		if(a[x][i] && i != fath){
			dfs(i,x);
		}
	}
}

int main()
{
    cin>>n;
    int x,y;
    for(int i = 1;i <= n - 1;i++){
    	cin>>x>>y;
    	a[x][y] = 1;
    	a[y][x] = 1;
	}
	cin>>u>>v;
	
	dfs(1,0);
	
	cout<<maxd<<endl<<maxw<<endl; 
	
	//找到u和v的最近公共祖先
	int tu = u,tv = v;
	while(u != v){
		if(dep[u] > dep[v]) u = fa[u];
		else v = fa[v];
	} 
	
	cout<<(dep[tu] - dep[u])*1 + dep[tv] - dep[u];
    return 0;
}