#include<cstdio>
#include<vector>
int max2(int a,int b){
    if(a>b)
        return a;
    return b;
}
using namespace std;
const int N=16000;
const int INF=1000;
vector<int>g[N+1];
int v[N+1];
int d[N+1];
bool vis[N+1];
int n,maxx=-INF-1;
void dfs(int dad){
    vis[dad]=true;
    d[dad]=v[dad];
    for(unsigned int i=0;i<g[dad].size();i++){
        int son=g[dad][i];
        if(!vis[son]){
            dfs(son);
            if(d[son]>0)
                d[dad]+=d[son];
        }
    }
    maxx=max2(maxx,d[dad]);
}
int main(){
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
        scanf("%d",&v[i]);
    for(int i=1;i<n;i++){
        int x,y;
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1);
    printf("%d",maxx);
    return 0;
}