#include <iostream>
#include <cstdio>
#include <vector>

using namespace std;

#define DIM 16005

vector <vector <int> > G;

int cost[DIM], viz[DIM], V[DIM], N;

int DF(int nod) {
    viz[nod] = 1;
    cost[nod] = V[nod];

    for(unsigned int z = 0; z < G[nod].size(); ++z) {
        if(viz[G[nod][z]] == 0) {
            int rez = DF(G[nod][z]);
            cost[nod] = max(cost[nod] + rez, cost[nod]);
        }
    }

    return cost[nod];
}

int main() {
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);

    scanf("%d\n", &N);

    int mxk = 1, pz = -1005;

    for(int i = 1; i <= N; ++i) {
        scanf("%d", &V[i]);

        if(pz < V[i]) {
            pz = V[i];
            mxk = i;
        }
    }

    G.resize(N + 1);

    int x, y;
    for(int i = 1; i < N; ++i) {
        scanf("%d %d\n", &x, &y);

        G[x].push_back(y);
        G[y].push_back(x);
    }

    DF(mxk);

    for(int i = 1; i <= N; ++i) {
        pz = max(pz, cost[i]);
    }

    cout << pz << '\n';

    return 0;
}