rt

# include <bits/stdc++.h>

# define I return

# define AK 0

# define IOI ;

typedef long long ll;

using namespace std;

int n, m, t, tot, x[10005], y[10005], a[10005], low[10005], dfn[10005], col[10005], s[10005], du[10005], dp[10005], maxx;

vector <int> v[10005];

stack <int> st;

queue <int> q;

void tarjan (int x) {

	low[x] = dfn[x] = ++ tot, st.push (x);

	for (const int& i : v[x])
		if (! dfn[i])
			tarjan (i), low[x] = min (low[x], low[i]);
		else if (! col[i])
			low[x] = min (low[x], dfn[i]);

	if (low[x] == dfn[x]) {

		col[x] = ++ t;

		while (st.top () != x)
			col[st.top ()] = t, st.pop ();

		st.pop ();

		return ;

	}

	return ;

}

int main () {

	ios::sync_with_stdio (0);

	cin.tie (0);

	cout.tie (0);

	cin >> n >> m;

	for (int i = 1; i <= n; ++ i)
		cin >> a[i];

	for (int i = 0; i < m; ++ i)
		cin >> x[i] >> y[i], v[x[i]].emplace_back (y[i]);

	for (int i = 1; i <= n; ++ i)
		if (! dfn[i])
			tarjan (i);
//	for (int i = 1; i <= n; ++ i) cerr << col[i] << ' ';
//	return 0;
	for (int i = 1; i <= n; ++ i)
		v[i].clear (), s[col[i]] += a[i];
//	for (int i = 1; i <= t; ++ i) cout << s[i] << ' ';
//	return 0;
	for (int i = 1; i <= t; ++ i)
		if (col[x[i]] != col[y[i]])
			++ du[col[y[i]]], v[col[x[i]]].emplace_back (col[y[i]]);

	for (int i = 1; i <= n; ++ i)
		if (! du[i])
			q.push (i);

	while (! q.empty ()) {

		const int x = q.front ();

		q.pop ();

		maxx = max (maxx, dp[x] += s[x]);

		for (const int& i : v[x])
			if (dp[i] = max (dp[i], dp[x]), ! -- du[i])
				q.push (i);

	}

	cout << maxx;

	I AK IOI;

}
/*
10 20
970 369 910 889 470 106 658 659 916 964
3 2
3 6
3 4
9 5
8 3
5 8
9 1
9 7
9 8
7 5
3 7
7 8
1 7
10 2
1 10
4 8
2 6
3 1
3 5
8 5
*/