#include<bits/stdc++.h>
using namespace std;
const int N=1e4+5,M=1e5+5;
int n,m;
int p[N];
int h[N],idx;
struct node{
	int v,ne,fr;
}e1[M],e2[M];
void ad1(int x,int y){
	e1[++idx].v=y,e1[idx].ne=h[x],e1[idx].fr=x,h[x]=idx;
}
int low[N],dfn[N],tim,sd[N];
int st[N],top;
bool vis[N];
void tarjan(int x){
	low[x]=dfn[x]=++tim;
	st[++top]=x,vis[x]=1;
	for(int i=h[x];i;i=e1[i].ne){
		int y=e1[i].v;
		if(!dfn[y]){
			tarjan(y);
			low[x]=min(low[x],low[y]);
		}
		else if(vis[y]){
			low[x]=min(low[x],dfn[y]);
		}
	}
	if(dfn[x]==low[x]){
		int y;
		while(y=st[top--]){
			sd[y]=x;
			vis[y]=0;
			if(x==y)break;
			p[x]+=p[y];
		}
	}
}
int in[N],dp[N];
void ad2(int x,int y){
	e2[++idx].v=y,e2[idx].ne=h[x],h[x]=idx,in[y]++;
}
queue<int>q;
void topu(){
	for(int i=1;i<=n;++i)if(!in[i])q.push(i);
	while(!q.empty()){
		int x=q.front();q.pop();
		for(int i=h[x];i;i=e2[i].ne){
			int y=e2[i].v;
			in[y]--;
			dp[y]=max(dp[y],dp[x]+p[y]);
			if(!in[y])q.push(y);
		}
	}
}
int ans;
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;++i)scanf("%d",&p[i]);
	for(int i=1;i<=m;++i){
		int u,v;
		scanf("%d%d",&u,&v);
		ad1(u,v);
	}
	for(int i=1;i<=n;++i)if(!dfn[i])tarjan(i);
	idx=0;
	for(int i=1;i<=m;++i){
		int x=sd[e1[i].fr],y=sd[e1[i].v];
		if(x!=y)ad2(x,y);
	}
	memcpy(dp,p,sizeof(dp));
	topu();
	for(int i=1;i<=n;++i)ans=max(ans,dp[i]);
	printf("%d",ans);
	return 0;
}