#include<bits/stdc++.h>
using namespace std;
const int maxn = 5000050;

int dfn[maxn],low[maxn],dfs_clock,sccno[maxn],scc_cnt;
stack<int> S;
int n,m;
int h[maxn],cnt,h1[maxn],cnt1;
int size[maxn];//记录每个强连通分量里的点权和; 
int a[100010];
int f[maxn],ans,maxnn;

struct node{
	int to,nxt;
}e[maxn],ee[maxn];

void add(int u,int v){
	e[++cnt].to = v;
	e[cnt].nxt = h[u];
	h[u] = cnt;
} 

void add1(int u,int v){
	ee[++cnt1].to = v;
	ee[cnt1].nxt = h1[u];
	h1[u] = cnt1;
} 

void tarjan(int u){
	dfn[u] = low[u] = ++dfs_clock;
	S.push(u);
	for(int i = h[u] ; i ; i = e[i].nxt){
		int v = e[i].to;
		if(!dfn[v]){
			tarjan(v);
			low[u] = min(low[u],low[v]);
		}
		else if(!sccno[v]){
			low[u] = min(low[u],dfn[v]);
		}
	}
	if(dfn[u] == low[u]){
		scc_cnt++;
		while(true){
			int v = S.top();
			S.pop();
			sccno[v] = scc_cnt;
			size[scc_cnt] += a[v]; 
			if(v == u){
				break;
			}
		}
	}
}

void search(int x){//记忆化搜索 
	if(f[x]){
		return;
	}
	f[x] = size[x];
	for(int i = h1[x] ; i ; i = ee[i].nxt){
		int v = ee[i].to;//遍历能到达的点;
		if(!f[v]){
			search(v);
		}
		maxnn = max(maxnn,f[v]); 
	}
	f[x] += maxnn;//不断记录更新f 
}

int main(){
	ios::sync_with_stdio(0),cin.tie(0);
	cin >> n >> m;
	for(int i = 1 ; i <= n ; i++){
		cin >> a[i];
	}
	for(int i = 1 ; i <= m ; i++){
		int u,v;
		cin >> u >> v;
		add(u,v);
	}
	for(int i = 1 ; i <= n ; i++){
		if(!dfn[i]){
			tarjan(i);
		}
	}
	for(int i = 1 ; i <= n ; i++){
		for(int j = h[i] ; j ; j = e[j].nxt){
			int v = e[j].to;
			int a = sccno[i];
			int b = sccno[v];
			if(a != b){
				add1(a,b);
			}
		}
	}
	for(int i = 1 ; i <= scc_cnt ; i++){
		if(!f[i]){//遍历新图的每一个点 
			search(i);
			ans = max(ans,f[i]);
		}
	}
	cout << ans << endl;
	return 0;
}