#include<cstdio>
#include<vector>

using namespace std;

int val[16010],x,y,ma=-16000000;
bool viz[16010];
vector<int> v[16010];
int n;

int solve(int nod)
{
    viz[nod]=1;
    int next;
    while(!v[nod].empty())
    {
        next=v[nod].back();
        if(viz[next]==0)
        {
            val[nod]+=solve(next);
        }
        v[nod].pop_back();
    }
    if(val[nod]>ma)
    {
        ma=val[nod];
    }
    if(val[nod]>0)
    {
        return val[nod];
    }
    return 0;
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);

    scanf("%d",&n);

    for(int i=1;i<=n;i++)
    {
        scanf("%d",&val[i]);
    }
    for(int i=1;i<n;i++)
    {
        scanf("%d %d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    solve(1);
    printf("%d",ma);
}