import heapq
n,m=map(int,input().split())
g=[[] for _ in range(n)]
for _ in range(m):
    a,b,c=map(int,input().split())
    g[a-1].append((b-1,c))
    g[b-1].append((a-1,c))
t=list(map(int,input().split()))
time=[[float('inf')]*1001 for _ in range(n)]
time[0][0]=0
q=[(0,0,0)]
while q:
    now_time,now_place,eat_time=heapq.heappop(q)
    if time[now_place][eat_time]<now_time:
        continue
    now_time+=t[now_place]
    eat_time=min(eat_time+t[now_place],1000)
    for to_place,to_dst in g[now_place]:
        if time[to_place][eat_time]>now_time+to_dst//eat_time:
            time[to_place][eat_time]=now_time+to_dst//eat_time
            heapq.heappush(q,(now_time+to_dst//eat_time,to_place,eat_time))
print(min(time[n-1]))