#include <bits/stdc++.h>

using namespace std;

const int N = 1e4 + 7;
vector <int> gra[N];
vector <int> e[N];
int head[N],dfn[N],low[N],s[N],w[N],id[N],rd[N],f[N];
int n,m,tp,dfncnt,sc;
bool insta[N];

void tarjan(int u){
	dfn[u] = low[u] = ++dfncnt;
	s[++tp] = u;
	insta[u] = 1;
	for(auto v : gra[u]){
		if(!dfn[v]){
			tarjan(v);
			low[u] = min(low[u],low[v]);
		}else if(insta[v]) low[u] = min(low[u],dfn[v]);
	}
	if(dfn[u] == low[u]){
		sc++;
		while(s[tp] != u){
			id[s[tp]] = sc;
			w[u] += w[s[tp]];
			w[s[tp]] = 0;
			insta[u] = 0;
			--tp;
		}
		id[s[tp]] = sc;
		insta[u] = 0;
		--tp;
	}
}

void dp(){
	queue <int> q;
	for(int i = 1;i <= n;i++){
		if(!rd[i]){
			q.push(i);
		}
	}
	while(!q.empty()){
		int u = q.front();
		q.pop();
		for(auto v : gra[u]){
			if(!(--rd[v])) q.push(v);
			f[v] = max(f[v],f[u] + w[v]);
		}
	} 
	int ans = 0;
	for(int i = 1;i <= n;i++) ans = max(ans,f[i]);
	printf("%d",ans);
}

int main(){
	scanf("%d%d",&n,&m);
	for(int i = 1;i <= n;i++) scanf("%d",&w[i]);
	int x,y;
	for(int i = 1;i <= m;i++){
		scanf("%d%d",&x,&y);
		gra[x].push_back(y);
	}
	for(int i = 1;i <= n;i++)
		if(!dfn[i]) tarjan(i);
	for(int i = 1;i <= n;i++){
		for(auto j : gra[i]){
			if(id[i] != id[j]){
				e[i].push_back(j);
				rd[j]++;
			}
		}
	}
	dp();
	return 0; 
}