#include<fstream>
#include<vector>
using namespace std;
#define k -200000000
#define NMax 16005
ifstream f("asmax.in");
ofstream g("asmax.out");
int n,i,value[NMax],viz[NMax],x,y,Smax,w[NMax];
vector<int> v[NMax];
void dfs(int x)
{
    viz[x]=1;
    int S=0;
    for(int i=0;i<v[x].size();++i)
        if(!viz[v[x][i]])
        {
            dfs(v[x][i]);
            if(w[v[x][i]]>0)
                S+=w[v[x][i]];
        }
    w[x]=value[x]+S;
    if(w[x]>Smax)
        Smax=w[x];
    viz[x]=0;
}
int main ()
{
    Smax=k;
    f>>n;
    for(i=1;i<=n;++i)
        f>>value[i];
    for(i=1;i<n;++i)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    g<<Smax;
    return 0;
}