#include <stdio.h>
#include <vector>
#define Nmax 16001
#define maxim(a,b)(a>b)?a:b
using namespace std;
int n,x,y;
bool viz[Nmax];
std::vector<int> v,G[Nmax],a;
void DFS(int x0)
{
    viz[x0] = true;
    a[x0] = v[x0];
    for(int i=0;i<G[x0].size();++i)
    {
        if(viz[G[x0][i]]==false)
        {
            DFS(G[x0][i]);
            if(a[G[x0][i]]>0)
            {
                a[x0]+=a[G[x0][i]];
            }
        }
    }
}
int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    v.push_back(0);
    a.resize(n+1);
    for(int i=1;i<=n;++i)
    {
        scanf("%d",&x);
        v.push_back(x);
    }
    for(int i=1;i<n;++i)
    {
        scanf("%d %d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1);
    int sumamax = -(1<<30);
    for(int i=1;i<=n;++i)
    {
        sumamax = maxim(sumamax,a[i]);
    }
    printf("%d",sumamax);
    return 0;
}