#include<cstdio>
#include<vector>
long long a[100005],b[100005];
std::vector<int>g[100005];
//0: delete, 1: have
long long f[100005][2];
int vis[100005];

long long max(long long a,long long b){ return a>b?a:b; }

void dp(int u){
    vis[u] = 1;
    f[u][0] = f[u][1] = 0;
    for(int v: g[u]){
        if(!vis[v]){
            dp(v);
            f[u][0] = f[u][0]+max(f[v][0],f[v][1]);
            f[u][1] = max(f[u][1]+f[v][0],f[u][1]+b[u]+b[v]+f[v][1]);
        }
    }
    f[u][0] += a[u];
    //printf("f[%d][0] = %lld, f[%d][1] = %lld\n",u,f[u][0],u,f[u][1]);
}

int main(){
    int n;
    scanf("%d",&n);
    for(int i = 1; i <= n; i++) scanf("%lld",&a[i]);
    for(int i = 1; i <= n; i++) scanf("%lld",&b[i]);
    for(int i = 1; i <= n-1; i++){
        int u,v;
        scanf("%d%d",&u,&v);
        g[u].push_back(v);
        g[v].push_back(u);
    }
    dp(1);
    printf("%lld\n",max(f[1][1],f[1][0]));
    return 0;
}