//2019.11.4 by ljz
//#pragma GCC optimize(2)
//email 573902690@qq.com
//if you find any bug in my code
//please tell me
#include<bits/stdc++.h>
//#include<ext/pb_ds/tree_policy.hpp>
//#include<ext/pb_ds/assoc_container.hpp>
using namespace std;
//using namespace __gnu_pbds;
//using namespace __gnu_cxx;
#define res register int
#define LL long long
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f
#define unl __int128
#define eps 1e-9
#define RG register
#define db double
//#define pc(x) __builtin_popcount(x)
#define ctz(x) __builtin_ctz(x)
#define pc(x) __builtin_popcountll(x)
typedef pair<int,int> Pair;
#define mp make_pair
#define fi first
#define se second
#define pi acos(-1.0)
#define pb push_back
#define ull unsigned LL
#define lowbit(x) (x&-x)
#define gc getchar
//template <class T>using Tree=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
//inline char gc() {
//    static char buf[100000],*p1,*p2;
//    return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
//}
//inline int read() {
//    res s=0,ch=gc();
//    while(ch<'0'||ch>'9')ch=gc();
//    while(ch>='0'&&ch<='9')s=s*10+ch-'0',ch=gc();
//    return s;
//}
//char sr[1<<21],z[20];
//int C=-1,Z=0;
//inline void Ot(){fwrite(sr,1,C+1,stdout),C=-1;}
//inline void print(res x){
//    if(C>1<<20)Ot();if(x<0)sr[++C]='-',x=-x;
//    while(z[++Z]=x%10+48,x/=10);
//    while(sr[++C]=z[Z],--Z);sr[++C]='\n';
//}
inline int read() {
    res s=0,ch=gc(),w=1;
    while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=gc();}
    while(ch>='0'&&ch<='9')s=s*10+ch-'0',ch=gc();
    return s*w;
}
inline LL Read() {
    RG LL s=0;
    res ch=gc();
    while(ch<'0'||ch>'9')ch=gc();
    while(ch>='0'&&ch<='9')s=s*10+ch-'0',ch=gc();
    return s;
}
//inline LL Read() {
//    RG LL s=0;
//    res ch=gc(),w=1;
//    while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=gc();}
//    while(ch>='0'&&ch<='9')s=s*10+ch-'0',ch=gc();
//    return s*w;
//}
//inline void write(RG unl x){
//    if(x>10)write(x/10);
//    putchar(int(x%10)+'0');
//}
inline void swap(res &x,res &y) {
    x^=y^=x^=y;
}
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//clock_t start=clock();
//inline void ck(){
//    if(1.0*(clock()-start)/CLOCKS_PER_SEC>0.1)exit(0);
//}
const int kcz=1000000007;
inline void add(res &x,const res &y){
    x+=y,x>=kcz?x-=kcz:(x<0?x+=kcz:1);
}
inline int Add(const res &x,const res &y){
    return x+y>=kcz?x+y-kcz:(x+y<0?x+y+kcz:x+y);
}
inline int mul(const res &x,const res &y){
    return int(1LL*x*y%kcz);
}
inline int mul(const res &x,const res &y,const res &d){
    return int(1LL*x*y/d%kcz);
}
inline int sqr(const res &x){
    return int(1LL*x*x%kcz);
}
inline int qpow(res x,res y){
    res ret=1;
    while(y){
        if(y&1)ret=mul(ret,x);
        x=mul(x,x),y>>=1;
    }
    return ret;
}
inline LL Qpow(RG LL x,res y){
    RG LL ret=1;
    while(y){
        if(y&1)ret*=x;
        x*=x,y>>=1;
    }
    return ret;
}
const int N=2e5+10;
namespace MAIN{
    int n;
//    int a[N];
//    vector<int> G[N];
//    int p[N];
    int cnt[N][2];
    struct P{
        int id,x,y;
        P() {}
        P(res id,res x,res y):id(id),x(x),y(y) {}
        inline bool operator < (const RG P &b) const {
            return 1LL*x*b.y<1LL*y*b.x;
        }
    };
    priority_queue<P> Q;
    int fa[N];
    inline int find(res x){
        while(x!=fa[x])x=fa[x]=fa[fa[x]];
        return x;
    }
    int p[N];
//    bool vis[N];
    inline void MAIN(){
        n=read();
        for(res i=2;i<=n;i++)p[i]=read();
        for(res i=1;i<=n;i++)cnt[fa[i]=i][read()]=1;
//        dfs(1);
//        res idx=0;
//        Q.push(P(1));
//        while(!Q.empty()){
//            res u=Q.top().id;
//            Q.pop(),p[++idx]=a[u];
//            for(auto tox:G[u])Q.push(P(tox));
//        }
//        RG LL ans=0;
//        for(res i=1;i<=idx;i++){
//            if(p[i]){s++;continue;}
//            ans+=s;
//        }
        RG LL ans=0;
        for(res i=2;i<=n;i++)Q.push(P(i,cnt[i][0],cnt[i][1]));
        while(!Q.empty()){
            RG P x=Q.top();
            Q.pop();
            if(x.x!=cnt[x.id][0]||x.y!=cnt[x.id][1])continue;
//            if(vis[x.id])continue;
//            vis[x.id]=1;
            res u=find(x.id),v=find(p[u]);
            ans+=1LL*cnt[v][1]*cnt[u][0],cnt[v][0]+=cnt[u][0],cnt[v][1]+=cnt[u][1],fa[u]=v;
            if(v!=1)Q.push(P(v,cnt[v][0],cnt[v][1]));
        }
        printf("%lld\n",ans);
    }
}
int main(){
//    freopen("money.in","r",stdin);
//    freopen("money.out","w",stdout);
//    srand(19260817);
    MAIN::MAIN();
//    Ot();
    return 0;
}


Measured memory_bytes: 7924