#1、4、5、6、7 WA Code:

#include <cstdio>
#include <algorithm>
#include <vector>
using namespace std;
const int N = 10010;
int r[N], v[N];
vector<int>g[N];
int n, root;
int dp[N][2];
void dfs(int x) {
    dp[x][0] = 0;
    dp[x][1] = r[x];
    for (int i = 0; i < g[x].size(); ++i) {
        int y = g[x][i];
        dfs(y);
        dp[x][0] += max(dp[y][0], dp[y][1]);
        dp[x][1] += dp[y][0];
    }
}
int main(){
    scanf("%d", &n);
    for (int i = 1; i <= n; ++i) scanf("%d", &r[i]);
    for (int i = 1; i < n; ++i) {
        int x, y;
        scanf("%d%d", &x, &y);
        g[y].push_back(x);
        v[i] = 1;
    }
    for (int i = 1; i <= n; ++i) {
        if (!v[i]) {
            root = i;
            break;
        }
    }
    dfs(root);
    printf("%d", max(dp[root][1], dp[root][0]));
    return 0;
}