#include <cstdio>
#include <vector>
#include <list>
#define NMAX 16001
using namespace std;

int n;
vector < list < int > > Tree;
int vizitat[NMAX],cost[NMAX],Sol[NMAX];
int MAXIM;

void citesc(){

    int x,y;
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    Tree.resize(n+1);
    for(register int i=1;i<=n;++i)
    scanf("%d",&cost[i]);
    for(register int i=1;i<n;++i){
        scanf("%d%d",&x,&y);
        Tree[x].push_back(y);
        Tree[y].push_back(x);
    }
}

void DFS(int root){

    vizitat[root] = 1;
    Sol[root] = cost[root];
        for(list < int >::iterator it = Tree[root].begin();it!=Tree[root].end();++it)
            if(!vizitat[*it]){
                DFS(*it);
              if(Sol[*it] > 0)
              Sol[root] += Sol[*it];
        }
MAXIM = max(MAXIM,Sol[root]);
}

int main(){

    citesc();
    MAXIM = (-1) * 0x3f3f3f3f;
    DFS(1);

   printf("%d",MAXIM);

return 0;
}