#include<cstdio>

 #define FFC(i,a,b) for(int i=a;i<=b;i++)

 #define max(a,b) ((a)>(b)?(a):(b))

 const int maxn=;

 int n,c[maxn],v[maxn],g[maxn],nxt[maxn],ed,xx,yy,ik,f[maxn],root,dp[maxn][];

 void adg(int x,int y){v[++ed]=y,nxt[ed]=g[x],g[x]=ed;}

 void fuck(int now){

     dp[now][]=c[now];

     for(int i=g[now];i;i=nxt[i]){

         fuck(v[i]);

         dp[now][]+=max(dp[v[i]][],dp[v[i]][]);

         dp[now][]+=dp[v[i]][];

     }

 }

 int main(){

     while(~scanf("%d",&n)){

         FFC(i,,n)scanf("%d",&c[i]);

         for(ik=ed=,root=;ik<=n;ik++)g[ik]=,f[ik]=ik;

         while(scanf("%d%d",&xx,&yy),xx+yy)adg(yy,xx),f[xx]=yy;

         FFC(i,,n)dp[i][]=dp[i][]=;

         while(f[root]!=root)root=f[root];

         fuck(root);

         printf("%d\n",max(dp[root][],dp[root][]));

     }

     return ;

 }