#include <cstdio>
#include <vector>

using namespace std;

#define Nmax 16050

int n, i, x, y, sol, S[Nmax], V[Nmax], viz[Nmax];
vector <int> A[Nmax];

void DFS(int nod) {
	int i, fiu;
	
	S[nod] = V[nod], viz[nod] = 1;
	for (i = 0; i < A[nod].size(); i++) {
		fiu = A[nod][i];
		if (!viz[fiu]) {
			DFS(fiu);
			
			if (V[nod] + S[fiu] > V[nod])
				S[nod] += S[fiu];
		}
	}
	
	if (S[nod] > sol)
		sol = S[nod];
}

int main() {
	
	FILE *f = fopen("asmax.in", "r");
	FILE *g = fopen("asmax.out", "w");
	
	fscanf(f, "%d", &n);
	
	for (i = 1; i <= n; i++)
		fscanf(f, "%d", &V[i]);
	
	for (i = 1; i < n; i++) {
		fscanf(f, "%d %d", &x, &y);
		A[x].push_back(y);
		A[y].push_back(x);
	}
	
	sol = 1 << 31;
	
	DFS(1);
	
	fprintf(g, "%d", sol);
	
	fclose(f); fclose(g);
	
	return 0;
}