#include<cstdio>
#include<vector>
using namespace std;
vector<int> a[16001];
int v[16001];
int rasp[16001];
char viz[16001];
void dfs(int x){
    viz[x]=1;
    int i;
    rasp[x]=v[x];
    for(i=0;i<a[x].size();i++)
        if (viz[a[x][i]]==0) {
            dfs(a[x][i]);
            if (rasp[a[x][i]]>0) rasp[x]+=rasp[a[x][i]];
    }
}
int main(){
    freopen ("asmax.in","r",stdin);
    freopen ("asmax.out","w",stdout);
    int n,i,x,y;
    scanf ("%d",&n);
    for(i=1;i<=n;i++)
        scanf ("%d",&v[i]);
    for(i=1;i<n;i++){
        scanf ("%d%d",&x,&y);
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    x=rasp[1];
    for(i=2;i<=n;i++)
        if (x<rasp[i]) x=rasp[i];
    printf ("%d",x);
    return 0;
}