#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<map>
#define Redge(u) for (int k = h[u],to; k; k = ed[k].nxt)
#define REP(i,n) for (int i = 1; i <= (n); i++)
#define mp(a,b) make_pair<int,int>(a,b)
#define cls(s) memset(s,0,sizeof(s))
#define cp pair<int,int>
#define LL long long int
using namespace std;
const int maxn = 300005,maxm = 8000005,INF = 1000000000,P = 998244353;
inline int read(){
    int out = 0,flag = 1; char c = getchar();
    while (c < 48 || c > 57){if (c == ‘-‘) flag = -1; c = getchar();}
    while (c >= 48 && c <= 57){out = (out << 3) + (out << 1) + c - 48; c = getchar();}
    return out * flag;
}
int n,Ls[maxn],Rs[maxn],b[maxn],N,v10000;
int rt[maxn],sum[maxm],ls[maxm],rs[maxm],tag[maxm],cnt;
int p[maxn],maxa,maxb;
inline int qpow(int a,int b){
    int re = 1;
    for (; b; b >>= 1,a = 1ll * a * a % P)
        if (b & 1) re = 1ll * re * a % P;
    return re;
}
inline void pd(int u){
    if (tag[u] > 1){
        sum[ls[u]] = 1ll * sum[ls[u]] * tag[u] % P;
        sum[rs[u]] = 1ll * sum[rs[u]] * tag[u] % P;
        tag[ls[u]] = 1ll * tag[ls[u]] * tag[u] % P;
        tag[rs[u]] = 1ll * tag[rs[u]] * tag[u] % P;
        tag[u] = 1;
    }
}
void modify(int& u,int l,int r,int pos){
    u = ++cnt; sum[u] = tag[u] = 1;
    if (l == r) return;
    int mid = l + r >> 1;
    if (mid >= pos) modify(ls[u],l,mid,pos);
    else modify(rs[u],mid + 1,r,pos);
}
int merge(int u,int v,int p){
    if (!u && !v) return 0;
    if (!u){
        maxb = (maxb + sum[v]) % P;
        int tmp;
        tmp = (((maxa + p) % P - 2ll * p * maxa % P) % P + P) % P;
        sum[v] = 1ll * sum[v] * tmp % P;
        tag[v] = 1ll * tag[v] * tmp % P;
        return v;
    }
    if (!v){
        maxa = (maxa + sum[u]) % P;
        int tmp;
        tmp = (((maxb + p) % P - 2ll * p  * maxb % P) % P + P) % P;
        sum[u] = 1ll * sum[u] * tmp % P;
        tag[u] = 1ll * tag[u] * tmp % P;
        return u;
    }
    pd(u); pd(v);
    int t = ++cnt; tag[t] = 1;
    rs[t] = merge(rs[u],rs[v],p);
    ls[t] = merge(ls[u],ls[v],p);
    sum[t] = (sum[ls[t]] + sum[rs[t]]) % P;
    return t;
}
void dfs(int u){
    if (!Ls[u]) modify(rt[u],1,N,p[u]);
    else if (!Rs[u]) dfs(Ls[u]),rt[u] = rt[Ls[u]];
    else {
        dfs(Ls[u]); dfs(Rs[u]);
        maxa = maxb = 0;
        rt[u] = merge(rt[Ls[u]],rt[Rs[u]],p[u]);
    }
}
int ans;
void cal(int u,int l,int r){
    if (l == r) {ans = (ans + 1ll * l * b[l] % P * sum[u] % P * sum[u] % P) % P;return;}
    pd(u);
    int mid = l + r >> 1;
    cal(ls[u],l,mid);
    cal(rs[u],mid + 1,r);
}
int main(){
    n = read(); read(); int x; v10000 = qpow(10000,P - 2);
    for (int i = 2; i <= n; i++){
        x = read();
        if (!Ls[x]) Ls[x] = i;
        else Rs[x] = i;
    }
    for (int i = 1; i <= n; i++){
        p[i] = read();
        if (!Ls[i]) b[++N] = p[i];
        else p[i] = 1ll * p[i] * v10000 % P;
    }
    sort(b + 1,b + 1 + N);
    for (int i = 1; i <= n; i++)
        if (!Ls[i]) p[i] = lower_bound(b + 1,b + 1 + N,p[i]) - b;
    dfs(1);
    cal(rt[1],1,N);
    printf("%d\n",ans);
    return 0;
}