INF = 1000000

def green(dist, color):
    green_ = -1
    minimum = INF
    for i, t in enumerate(dist):
        if t < minimum and i not in color:
            minimum = t
            green_ = i
    return green_

n = int(input())
cost = list(map(int, input().split()))
graph = [[0] * n for i in range(n)]
m = int(input())
for i in range(m):
    a1, a2 = map(int, input().split())
    graph[a1-1][a2-1] = cost[a1-1]
    graph[a2-1][a1-1] = cost[a2-1]

f = n - 1
v = 0
dist = [INF] * n
color = {v}
dist[v] = 0

while v != -1:
    for j, dw in enumerate(graph[v]):
        if j not in color and dist[v] + dw < dist[j] and dw > 0:
            dist[j] = dist[v] + dw
    v = green(dist, color)
    color.add(v)

if dist[f] == INF:
    print(-1)
else:
    print(dist[f])