#define _CRT_SECURE_NO_WARNINGS

#include <cstdio>
#include <cstdlib>

//#define DEBUG

#ifdef DEBUG
#define dprintf(...) fprintf(stderr, __VA_ARGS__)
#else
#define dprintf(...) do{}while(0)
#endif

using namespace std;

#define N_MAX 16001

int n;
long long v[N_MAX];
int grad[N_MAX];
int *vecini[N_MAX];
int vecini_data[2 * N_MAX];
int muchie_a[N_MAX];
int muchie_b[N_MAX];
int viz[N_MAX];


static inline void readData() {
	scanf("%d", &n);

	for(int i = 0; i < n; ++i)
		grad[i] = 0;

	for(int i = 0; i < n; ++i)
		scanf("%lld", v + i);

	int a, b;
	for(int i = 0; i < n - 1; ++i) {
		scanf("%d %d", &a, &b);
		a--;
		b--;
		grad[a]++;
		grad[b]++;
		muchie_a[i] = a;
		muchie_b[i] = b;
	}

	for(int i = 0; i < n; ++i) 
		vecini[i] = (i == 0 ? vecini_data : (vecini[i - 1] + grad[i - 1]));

	for(int i = 0; i < n - 1; ++i) {
		a = muchie_a[i];
		b = muchie_b[i];
		vecini[a][0] = b;
		vecini[b][0] = a;
		vecini[a]++;
		vecini[b]++;
	}

	for(int i = 0; i < n; ++i) 
		vecini[i] = (i == 0 ? vecini_data : (vecini[i - 1] + grad[i - 1]));

}


int main() {

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

	readData();

#ifdef DEBUG
	for(int i = 0; i < n; ++i) {
		dprintf("%d: ", i + 1);
		for(int j = 0; j < grad[i]; ++j)
			dprintf("%d ", vecini[i][j] + 1);
		dprintf("\n");
	}
#endif


	int *s = muchie_a;
	int *fii = muchie_b;
	int vf = -1;
	int x, p;
	long long max = v[0];

	for(int i = 0; i < n; ++i) {
		max = max > v[i] ? max : v[i];
		viz[i] = 0;
		fii[i] = grad[i];
		if(grad[i] == 1)
			s[++vf] = i;
	}

	while(vf >= 0) {
		x = s[vf--];
		viz[x] = 1;
		p = 0;
		for(int i = 0; i < grad[x]; ++i)
			if(viz[vecini[x][i]] == 0) {
				p = vecini[x][0];
				break;
			}

		//contribui
		if(v[x] > 0) 
			v[p] += v[x];

		fii[p]--;
		if(fii[p] == 1)
			s[++vf] = p;

		if(fii[p] == 0) {
			if(v[p] >= 0)
				max = v[p];
			dprintf("%lld\n", max);
			printf("%lld\n", max);
			break;
		}
		
	}

	fclose(stdout);
	return 0;
}