#include<bits/stdc++.h>

#define re register
#define il inline
#define inf 0x3f3f3f3f
#define Wanderer 0

using namespace std;

const int MAXN = 1e5+5;
int n, m;
int tot, head1[MAXN], head2[MAXN], sum, val[MAXN], valat[MAXN];
int dfn[MAXN], low[MAXN], cnt, at[MAXN], num, vis[MAXN], dp[MAXN], ans, maxx = -inf;
bool book[MAXN];

stack <int> s;

struct node {
	int to, next;
} edge[MAXN], now[MAXN];

il void add1(int x, int y) {
	edge[++tot].next = head1[x];
	edge[tot].to = y;
	head1[x] = tot;
}

il void add2(int x, int y) {
	now[++sum].next = head2[x];
	now[sum].to = y;
	head2[x] = sum;
}

void tarjan(int u) {
	dfn[u] = low[u] = ++cnt;
	s.push(u);
	book[u] = true;
	for (re int k = head1[u]; k; k = edge[k].next) {
		int v = edge[k].to;
		if (!dfn[v]) {
			tarjan(v);
			low[u] = min(low[u], low[v]);
		} else if (book[v])
			low[u] = min(low[u], low[v]);
	}
	if (dfn[u] == low[u]) {
		num++;
		int t;
		do {
			t = s.top();
			s.pop();
			book[t] = false;
			at[t] = num;
		} while (t != u);
	}
}

il void build() {
	for (re int i = 1; i <= n; ++i)
		for (re int j = head1[i]; j; j = edge[j].next)
			if (at[i] != at[edge[j].to]) {
				add2(at[i], at[edge[j].to]);
				vis[at[edge[j].to]]++;
			}
	for (re int i = 1; i <= n; ++i)
		valat[at[i]] += val[i];
}

il void toposort() {
	queue <int> q;
	for (re int i = 1; i <= num; ++i)
		if (!vis[i])
			q.push(i);
	while (!q.empty()) {
		int v = q.front();
		int ans = dp[v] = valat[v];
		q.pop();
		for (re int i = head2[v]; i; i = now[i].next) {
			dp[now[i].to] = valat[now[i].to] + ans;
			ans = dp[now[i].to];
		}
		if (!(--vis[now[v].to]))
			q.push(vis[now[v].to]);
	}
	for (re int i = 1; i <= num; ++i)
		maxx = max(dp[i], maxx);
	cout << maxx << endl;

}

int main() {
	cin >> n >> m;
	for (re int i = 1; i <= n; ++i)
		cin >> val[i];
	for (re int i = 1; i <= m; ++i) {
		int x, y;
		cin >> x >> y;
		add1(x, y);
	}
	for (re int i = 1; i <= n; ++i)
		if (!dfn[i])
			tarjan(i);
	build();
	toposort();
	return Wanderer;
}