#include<cstdio>
#include<vector>
using namespace std;
struct nod{
    int val,sum,viz;
    vector <int> v;
};
nod g[16001];
int maxi=-1001;
void dfs(int nod){
    int i,fiu;
    g[nod].viz=1;
    g[nod].sum=g[nod].val;
    for(i=0;i<g[nod].v.size();i++)
        if(!g[g[nod].v[i]].viz){
            dfs(g[nod].v[i]);
            fiu=g[nod].v[i];
            if(g[fiu].sum>0)
                g[nod].sum+=g[fiu].sum;
        }
    if(g[nod].sum>maxi)
        maxi=g[nod].sum;
}
int main(){
    int n,i,a,b;
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        scanf("%d",&g[i].val);
    for(i=1;i<=n-1;i++){
        scanf("%d%d",&a,&b);
        g[a].v.push_back(b);
        g[b].v.push_back(a);
    }
    dfs(1);
    printf("%d",maxi);
    return 0;
}