#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <bitset>
#include <cstdio>
#include <string>
#include <iomanip>
#include <cstring>
#include <cmath>
#include <vector>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>
#include <map>
#include <set>
#include <queue>
#include <stack>
#define lowbit(x) x&(-x)
#define pi 3.14159265358
#define lc k<<1;
#define rc k<<1|1
#define ppb push_back
#define mod 1000000007
#define fori(i,l,r) for(int i=l;i<=r;i++)
#define forj(j,l,r) for(int j=l;j<=r;j++)
using namespace std;
typedef long long ll;
typedef unsigned long long ULL;
typedef pair <int, int> pll;
const int N = 2e5 + 10;
const int P = 131;
ll t, n, m,a,b;
double aa = 0, bb = 0;
ll ans = 0;
ll arr[N];
ll w[N];
ll as[N];
vector<ll>e[N];
vector<ll>v[N];
map<int, int>mp;
bool p[N];
void dfs1(int x){
	for (auto c : v[x]){
		if (!mp[c]){
			mp[c] = 1;
			as[arr[c]] += w[c];
			dfs1(c);
			mp[c] = 0;
		}
	}
}
void ac(){
	cin >> n >> m;
	
	for (int i = 1; i <= n; i++){
		cin >> arr[i];
		if (arr[i] == 1)mp[i] = 1;
		e[arr[i]].push_back(i);
	}for (int i = 1; i <= n; i++)cin >> w[i];
	for (int i = 1; i <= m; i++){
		cin >> a >> b;
		v[a].push_back(b);
	}for (auto c : e[1]){
		bb = w[c];
		mp[c] = 1;
		dfs1(c);
		mp[c] = 0;
		for (int i = 2; i <= n; i++){
			double vv = as[i] / bb;
			ll ad = floor(vv);
			ans = max(ans, ad);
			as[i] = 0;
		}
	}cout << ans;

}
int main() {
	ios::sync_with_stdio(0);
	cin.tie();
	cout.tie();
	t = 1;
	while (t--){
		ac();
	}

}