#include <bits/stdc++.h>
using std::cin;
using std::cerr;
using std::cout;
using std::queue;
#define ll long long
#define db double
#define LL __int128
#define pii pair<int,int>
#define sec second
#define fir first
#define Gc getchar
#define R() IO::read()
#define add push_back
#define W(x) write(x)
const int N=16005;
namespace IO{
	int read(void){
		int x=0;
		char ch=0;
		while(!isdigit(ch)) ch=Gc();
		while(isdigit(ch)) x=(x<<1)+(x<<3)+(ch^48),ch=Gc();
		return x;
	}
	void write(int x){
		if(x>9) write(x/10);
		putchar(x%10^48);
	}
}
namespace Graph{
	std::vector<int> G[N],T[N];
	int col[N],stack[N],dfn[N],low[N],val[N],a[N];
	int f[N];
	int top,tot;
	int n,m,Cnt;
	std::bitset<N> vis;
	void Init_Input(void){
		n=R(),m=R();
		for(int i=1;i<=n;++i)
			a[i]=R();
		for(int i=1;i<=m;++i){
			int ai=R(),aj=R();
			G[ai].add(aj);
		}
	}
	void Tarjan(int u){
		dfn[u]=low[u]=++tot;
		stack[++top]=u;
		vis[u]=true;
		for(int v:G[u]){
			if(!dfn[v]) Tarjan(v),low[u]=std::min(low[v],low[u]);
			else if(vis[v])  low[u]=std::min(low[u],dfn[v]);
		} if(dfn[u]==low[u]){
			++Cnt;
			while(stack[top]!=u){
				col[stack[top]]=Cnt;
				val[Cnt]+=a[stack[top]];
				vis[stack[top]]=0;
				top--;
			}
			col[stack[top]]=Cnt;
			val[Cnt]+=a[stack[top]];
			vis[stack[top]]=0;
			top--;
		}
	}
	int ans=0;
	void Debug(void){
		for(int i=1;i<=n;++i){
			printf("col [ %d ] -> %d\n",i,col[i]);
		}
	}
	void Run(void){
		Init_Input();
		for(int i=1;i<=n;++i)
			if(!dfn[i]) Tarjan(i);
		for(int i=1;i<=n;++i){
			for(int v:G[i])
				if(col[i]!=col[v])
					T[col[i]].add(col[v]);
		}
		for(int i=Cnt;i;--i){
			f[i]+=val[i];
			ans=std::max(ans,f[i]);
			for(int v:T[i]) f[v]=std::max(f[v],f[i]);
		}
	}
	void Output(){ IO::W(ans);putchar('\n'); }
}
int main(){ Graph::Run();Graph::Output(); }