import java.io.*;

class Main{
    static StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
    static PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
    static int nextInt() throws Exception{
        in.nextToken();
        return (int)in.nval;
    }

    static int[] h, e, ne, v;
    static int idx = 0;
    static int[][] f;

    static void add(int a, int b){
        e[idx] = b;
        ne[idx] = h[a];
        h[a] = idx++;
    }

    static void DFS(int root){
        //if(f[root][1]&&f[root][0]>0) return;
        int sum0, sum1;
        sum0 = 0; sum1 = 0;
        for(int i=h[root]; i!=-1; i=ne[i]){
            int r = e[i];
            DFS(r);
            sum0 += f[r][1];
            sum1 += f[r][0];
        }
        f[root][1] = -0x3f3f3f3f;
        f[root][0] = -0x3f3f3f3f;
        f[root][1] = sum1+v[root];
        f[root][0] = Math.max(sum1, sum0);

    }

    public static void main(String[] args)throws Exception{
        int n = nextInt();
        h = new int[n+1];
        e = new int[n];
        ne = new int[n];
        f = new int[n+1][2];
        v = new int[n+1];
        for(int i=1; i<=n; i++){
            v[i] = nextInt();  
            h[i] = -1;
        }
        boolean[] roots = new boolean[n+1];
        for(int i=0; i<n-1; i++){
            int a, b;
            b = nextInt(); a = nextInt();
            add(a, b);
            roots[b] = true;
        }
        int root=0;
        for(int i=1; i<=n; i++) if(!roots[i]) root = i;
        //out.print(root);

        DFS(root);
        out.print(Math.max(f[root][0],f[root][1]));
        out.close();
    }
}