#include <stdio.h>
#include <stdlib.h>

int n, i, v, s, e;

typedef struct nod {
    long int val;
    int index;
    struct nod *child;
    struct nod *sibling;
} nod;

nod *nodes[16001];

inline int max(int a, int b) {
    return a > b ? a : b;
}

unsigned long long solve(nod *root) {
    int i = 0, j;
    int sums[16000];
    int ms = 0;

    if (root == NULL) return 0;

    nod *c = root->child;
    while (c) {
        sums[i++] = solve(c);
        c = c->sibling;
    }

    for (j = 0; j < i; j++) {
        ms += max(sums[j], 0);
    }

    return max(ms + root->val, 0);
}

int main() {
    nod *x;
    unsigned int esum = 0;
    FILE *fi, *fo;
    fi = freopen("asmax.in", "r", stdin);
    fo = freopen("asmax.out", "w", stdout);
    scanf("%d", &n);
    for(i=1;i<=n;i++) {
        scanf("%d", &v);
        x = (nod*) malloc(sizeof(nod));
        x->val = v;
        x->index = i;
        nodes[i] = x;
    }
    for(i = 1; i < n; i++) {
        scanf("%d %d", &s, &e);
        nodes[e]->sibling = nodes[s]->child;
        nodes[s]->child = nodes[e];
        esum += e;
    }
    printf("%llu\n", solve(nodes[(n * (n + 1))/2 - esum]));
    fclose(fi);
    fclose(fo);
    return 0;
}