#include<cstdio>
#include<vector>
using namespace std;

const int NMAX=16005;

int dp[NMAX],maxx=-17000;
vector<int> G[NMAX];

void dfs(int nod, int tata){
    for(int i=0;i<(int)G[nod].size();i++){
        int fiu=G[nod][i];
        if(fiu!=tata){
            dfs(fiu, nod);
            if(dp[fiu]>0)
                dp[nod]+=dp[fiu];
        }
    }
    maxx=max(maxx, dp[nod]);
}

int main(){
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    int n;
    scanf("%d", &n);
    for(int i=1;i<=n;i++)
        scanf("%d", &dp[i]);
    for(int i=1;i<n;i++){
        int a,b;
        scanf("%d%d", &a, &b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
    dfs(1, 0);
    printf("%d", maxx);
    return 0;
}