#include <cstdio>
        #include <cstring>
        #include <vector>
        using namespace std;
        vector <int> g[16001];
        int a[16001], Max=-10000000;
        bool sel[16001];
        void dfs (int x)
        {
            int i; sel[x]=true;
            for (i=0; i<g[x].size(); i++)
            {
                if (!sel[g[x][i]])
                {
                    dfs(g[x][i]);
                    sel[g[x][i]]=true;
                    if (a[g[x][i]]>0)
                    {
                        a[x]+=a[g[x][i]];
                    }
                }
            }
            if (a[x]>Max) Max=a[x];
        }
        int main()
        {
            int n, i, j, x, y;
            bool plus=false;
            freopen("asmax.in","r",stdin);
            freopen("asmax.out","w",stdout);
            scanf("%d",&n);
            for (i=1; i<=n; i++)
            {
                scanf("%d",&a[i]);
                if (a[i]>Max) Max=a[i];
            }
            for (i=1; i<n; i++)
            {
                scanf("%d%d",&x,&y);
                g[x].push_back(y);
                g[y].push_back(x);
            }
            dfs(1);
            printf("%d\n",Max);
            fclose(stdin);
            fclose(stdout);
            return 0;
        }