from collections import defaultdict
import heapq
n,m=map(int,input().split())
a=list(map(int,input().split()))
E = defaultdict(list)
Eprev = defaultdict(list)
cnt = defaultdict(int)
out = defaultdict(int)
for _ in range(m):
	u,v = map(int, input().split())
	E[u].append(v)
	Eprev[v].append(u)
	cnt[v]+=1
	out[u]+=1
ans = 0
count = 0
f = [0]*n #最早结束时间
q = []
for i in range(1,1+n):
	if cnt[i]==0:
		q.append((a[i-1], i))  # 最早结束时间，i
heapq.heapify(q)
while q:
	cur_time, node = heapq.heappop(q)
	f[node-1] = cur_time
	ans = max(ans, cur_time)
	for nxt in E[node]:
		cnt[nxt]-=1
		if cnt[nxt]==0:
			heapq.heappush(q, (cur_time+a[nxt-1], nxt))
print(ans)
idx = []
g = [ans]*n # 最晚结束时间
q = []
for i in range(n):
	if out[i+1]==0: # 后继没点了
		q.append(i+1)
while q:
	t = []
	for i in q:
		for prev in Eprev[i]:
			g[prev-1] = min(g[prev-1], g[i-1]-a[i-1])
			out[prev]-=1
			if out[prev]==0:
				t.append(prev)
	q = t
total = 1
mod = 10**9+7
for gi,fi i...