#include <cstdio>
#define nmax 16002
#include <queue>
#include <algorithm>
#include <stack>
#include <vector>

using namespace std;

int N,d[nmax],v[nmax],rez=0,s[nmax],t[nmax];
bool viz[nmax];
queue <int> Q;
stack <int> S;
vector <int> V[nmax];

int main(){
  
  freopen("asmax.in","r",stdin);
  freopen("asmax.out","w",stdout);

  scanf("%d ",&N);
  int i,x,y;
  for(i = 1;i <= N;++i){
    scanf("%d ",&v[i]);
    s[i] = v[i];
    rez = min(rez,v[i]);
  }
  
  for(i=1;i < N;++i){
    scanf("%d %d ",&x,&y);
    V[x].push_back(y);
    V[y].push_back(x);
    d[x]++;d[y]++;
  }

  t[1] = 0;
  S.push(1);
  while(!S.empty()){
    x = S.top();
    S.pop();
    if(viz[x] == 0){
      viz[x] = 1;
      if(d[x] == 1)Q.push(x);
      else
	for(vector <int> :: iterator it = V[x].begin();it != V[x].end();++it)
	  {
	   S.push(i);
	   t[i] = x;
	  }
    }
  }
  
  while(!Q.empty()){
    x = Q.front();
    Q.pop();
    s[t[x]] = max(s[t[x]],s[t[x]]+s[x]);
    d[t[x]]--;d[x]--;
    if(d[t[x]] == 1)Q.push(t[x]);
    rez = max(s[x],rez);
  }
  
  printf("%d\n",rez);

  return 0;
}