#include <cstdio>
#include <vector>
using namespace std;

#define MAXN 16384

int N;
short int V[MAXN]
int P[MAXN];
vector <short int> L[MAXN];

void read_data()
{
    scanf("%d", &N);
    for(int i=1; i<=N; ++i)
        scanf("%hd", &V[i]);
    for(int i=0; i<N-1; ++i)
    {
        int u, v;
        scanf("%d %d", &u, &v);
        L[u].push_back(v);
        L[v].push_back(u);
    }
}

void DF(int v, int father)
{
    for(size_t i=0; i<L[v].size(); ++i)
        if(L[v][i]!=father)
            DF(L[v][i], v);
    P[v]=V[v];
    for(size_t i=0; i<L[v].size(); ++i)
        if(L[v][i]!=father && P[L[v][i]]>0)
            P[v]+=P[L[v][i]];
}


int main()
{
    freopen("asmax.in", "r", stdin);
    freopen("asmax.out", "w", stdout);
    read_data();
    DF(1, 0);
    int poz=1;
    for(int i=2; i<=N; ++i)
        if(P[i] > P[poz])
            poz=i;
    printf("%d\n", P[poz]);
    return 0;
}