#include <cstdio>
#include <iostream>
#include <vector>
#define MAXN 16001
using namespace std;
vector <int> v[MAXN];
int d[MAXN];
bool viz[MAXN];
void dfs(int nod)
{
    viz[nod]=true;
    for(unsigned int i=0;i<v[nod].size();i++)
        if(!viz[v[nod][i]])
        {
            dfs(v[nod][i]);
            if(d[v[nod][i]]>0)
                d[nod]+=d[v[nod][i]];
        }
}
int main()
{
    FILE *fin,*fout;
    fin=fopen("asmax.in","r");
    fout=fopen("asmax.out","w");
    int n,x,y;
    fscanf(fin,"%d",&n);
    for(int i=1;i<=n;i++)
        fscanf(fin,"%d",&d[i]);
    for(int i=1;i<n;i++)
    {
        fscanf(fin,"%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    fprintf(fout,"%d",d[1]);
    fclose(fin);
    fclose(fout);
    return 0;
}