#include<stdio.h>
#include<stdlib.h>
#define Nm 16001
#define Inf Nm*1000
int V[Nm],X[Nm],Y[Nm],n;
int *G[Nm],D[Nm],Asm[Nm],asmax;

void read()
{
    int i,x,y;

    freopen("asmax.in","r",stdin);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
	scanf("%d",V+i);
    for(i=1;i<n;i++)
	scanf("%d%d",X+i,Y+i);
}

void DFS(int x, int tx)
{
    int i;

    Asm[x]=V[x];
    for(i=0;i<D[x];i++)
	if(G[x][i]!=tx)
	{
	    DFS(G[x][i],x);
	    if(Asm[G[x][i]]>0)
		Asm[x]+=Asm[G[x][i]];
	}

    if(Asm[x]>asmax)
	asmax=Asm[x];
}

void solve()
{
    int i;

    for(i=1;i<n;i++)
    {
	D[X[i]]++;
	D[Y[i]]++;
    }

    for(i=1;i<=n;i++)
    {
	G[i]=(int*)malloc(D[i]*sizeof(int));
	D[i]=0;
    }

    for(i=1;i<n;i++)
    {
	G[X[i]][D[X[i]]++]=Y[i];
	G[Y[i]][D[Y[i]]++]=X[i];
    }

    asmax=-Inf;
    DFS(1,0);
}

void write()
{
    freopen("asmax.out","w",stdout);
    printf("%d\n",asmax);
}

int main()
{
    read();
    solve();
    write();
    return 0;
}