#include<fstream>
#include<vector>
using namespace std;
int n,i,j,c[16010],sum[16010],x,y,max1=-1000000000,viz[16010];
vector <int>a[16010];
void dfs(int x)
{
    int i;
    sum[x]=c[x];
    viz[x]=1;
    for(i=0;i<a[x].size();++i)
        if(!viz[a[x][i]])
        {
            viz[a[x][i]]=1;
            dfs(a[x][i]);
            if(sum[a[x][i]]>0)
                sum[x]+=sum[a[x][i]];
        }
}
int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
    scanf("%d",&c[i]);
    for(i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        a[x].push_back(y);
        a[y].push_back(x);
        //a[x][0]++;
        //a[x][a[x][0]]=y;
        //a[y][0]++;
        //a[y][a[y][0]]=x;
    }
    dfs(1);
    for(i=1;i<=n;i++)
    if(sum[i]>max1)
    max1=sum[i];
    printf("%d",max1);
    return 0;
}