from heapq import heappush, heappop
n,m = map(int,input().split())

e = [[] for i in range(n)]
for i in range(m):
    a,b,c = map(int,input().split())
    a -= 1
    b -= 1
    e[a].append((b,c))
    e[b].append((a,c))
T = list(map(int,input().split()))

inf = 10**10
dis = [inf]*n

h = [(0,0,0)]
while h:
    d,p,now = heappop(h)
    p *= -1
    if dis[now] <= d:
        continue
    dis[now] = d
    p += T[now]
    for nex,c in e[now]:

        if dis[nex] > dis[now]+T[now]+c//p:
            heappush(h, (dis[now]+T[now]+c//p,-p,nex))
print(dis[-1])