#include<bits/stdc++.h>

#define LL long long

#define fi first

#define se second

#define mk make_pair

#define PLL pair<LL, LL>

#define PLI pair<LL, int>

#define PII pair<int, int>

#define SZ(x) ((int)x.size())

#define ull unsigned long long

using namespace std;

const int N = 1e6 + ;

const int inf = 0x3f3f3f3f;

const LL INF = 0x3f3f3f3f3f3f3f3f;

const int mod = 1e9 + ;

const double eps = 1e-;

const double PI = acos(-);

LL n, T, t[N], cnt[N], dp[N], ans[N];

vector<PLI> G[N];

#define lson l,mid,rt<<1

#define rson mid+1,r,rt<<1|1

LL a[N<<], sum[N<<];

void update(int p, LL val, int l=, int r=, int rt=) {

    if(l == r) {

        a[rt] += val;

        sum[rt] += val*p;

        return;

    }

    int mid = l + r >> ;

    if(p <= mid) update(p, val, lson);

    else update(p, val, rson);

    a[rt] = a[rt<<] + a[rt<<|];

    sum[rt] = sum[rt<<] + sum[rt<<|];

}

LL query(LL res, int l=, int r=, int rt=) {

    if(sum[rt] <= res) return a[rt];

    if(l == r) return res / l;

    int mid = l + r >> ;

    if(res <= sum[rt<<]) return query(res, lson);

    else return query(sum[rt<<], lson) + query(res-sum[rt<<], rson);

}

void getDp(int u, LL res) {

    update(t[u], cnt[u]);

    dp[u] = query(res);

    for(auto e : G[u]) getDp(e.se, res-e.fi);

    update(t[u], -cnt[u]);

}

void dfs(int u) {

    ans[u] = dp[u];

    if(u == ) {

        LL mx = ;

        for(auto e : G[u]) dfs(e.se), mx = max(mx, ans[e.se]);

        ans[u] = max(ans[u], mx);

    } else {

        LL mx = , mx2 = ;

        for(auto e : G[u]) {

            dfs(e.se);

            if(ans[e.se] >= mx) mx2 = mx, mx = ans[e.se];

            else if(ans[e.se] > mx2) mx2 = ans[e.se];

        }

        ans[u] = max(ans[u], mx2);

    }

}

int main() {

    cin >> n >> T;

    for(int i = ; i <= n; i++) cin >> cnt[i];

    for(int i = ; i <= n; i++) cin >> t[i];

    for(int i = ; i <= n; i++) {

        LL p, l; cin >> p >> l;

        G[p].push_back(mk(l<<, i));

    }

    getDp(, T);

    dfs();

    printf("%lld\n", ans[]);

    return ;

}

/*

*/