#include<bits/stdc++.h>
using namespace std;
#define int long long
const int M=2e5+5;
int a[M],dp[M],in[M],cn,cnt,sta[M],low[M],dfn[M],sum[M];
vector<int>f[M],ff[M];
int top,belong[M];
void dfs(int now) {
	dfn[now]=low[now]=++cn;
	sta[++top]=now;
	in[now]=1;
	for(auto to:f[now])
		if(!dfn[to])dfs(to),low[now]=min(low[now],low[to]);
		else if(in[to])low[now]=min(low[now],dfn[to]);
	if(dfn[now]==low[now]) {
		++cnt;
		int y;
		do {
			y=sta[top--];
			in[y]=0;
			sum[cnt]+=a[y];
			belong[y]=cnt;
		} while(now!=y);
	}
}
int ru[M],chu[M];
void solve() {
	int n,m;
	cin>>n>>m;
	for(int i=1; i<=n; ++i)cin>>a[i];
	while(m--) {
		int x,y;
		cin>>x>>y;
		f[x].push_back(y);
	}
	for(int i=1; i<=n; ++i)if(!dfn[i])dfs(i);
	for(int i=1; i<=n; ++i)
		for(auto to:f[i])
			if(belong[i]!=belong[to])
				ru[belong[to]]++,chu[belong[i]]++,ff[belong[i]].push_back(belong[to]);
	queue<int>p;
	for(int i=1; i<=cnt; ++i) {
		dp[i]=sum[i];
		if(ru[i]==0)p.push(i);
	}
	while(!p.empty()) {
		int t=p.front();
		p.pop();
		for(auto to:ff[t]) {
			dp[to]=max(dp[to],sum[to]+dp[t]);
			if(!--ru[to])p.push(to);
		}
	}
	int ans=0;
	for(int i=1; i<=n; ++i)ans=max(ans,dp[i]);
	cout<<ans;
}
signed main() {
	ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	int t=1;
	//cin>>t;
	while(t--)solve();
	return 0;
}