#include <stdio.h>
#include <vector>

#define NMAX 16005
using namespace std;

vector<int> v[NMAX];

int N, val[NMAX], viz[NMAX], maxim;

void dfs(int x){
    viz[x] = 1;
    int y;
    for (int i = 0; i < v[x].size(); i++){
        y = v[x][i];
        if(viz[y] == 0){
            dfs(y);
            if(val[y] > 0){
                val[x] += val[y];
                if(val[x] > maxim){
                    maxim = val[x];
                }
            }
        }
    }
}


int main()
{
    freopen("asmax.in", "r", stdin);
    freopen("asmax.out", "w", stdout);
    scanf("%d", &N);
    int i, a, b;
    for (i = 1; i <= N; i++){
        scanf("%d", &val[i]);
    }

    for(i = 1; i < N; i++){
        scanf("%d%d", &a, &b);
        v[a].push_back(b);
        v[b].push_back(a);
    }

    dfs(1);

    printf("%d", maxim);

    return 0;
}