n,m=map(int,input().split())
l=[list(map(int,input().split())) for i in range(m)]
t=list(map(int,input().split()))

import heapq
def dijkstra_heap(s,list,n):
  edge=list
  d=[10**18]*n
  used=[True]*n 
  d[s]=0
  used[s]=False
  edgelist=[]
  for e in edge[s]:
    heapq.heappush(edgelist,e)
  while len(edgelist):
    minedge=heapq.heappop(edgelist)
    if not used[minedge[1]]:
      continue
    v=minedge[1]
    d[v]=minedge[0]
    used[v]=False
    for e in edge[v]:
      if used[e[1]]:
        heapq.heappush(edgelist,(e[0]+d[v],e[1]))
  return d

edge=[[] for i in range(n*1001)]
for i in range(m):
  for j in range(1001):
    if j+t[l[i][0]-1]>0:
      edge[j*n+(l[i][0]-1)].append((t[l[i][0]-1]+l[i][2]//(j+t[l[i][0]-1]),min(j+t[l[i][0]-1],1000)*n+l[i][1]-1))
    if j+t[l[i][1]-1]>0:
      edge[j*n+(l[i][1]-1)].append((t[l[i][1]-1]+l[i][2]//(j+t[l[i][1]-1]),min(j+t[l[i][1]-1],1000)*n+l[i][0]-1))

l=dijkstra_heap(0,edge,n*1001)
ans=[]
for i in range(1001):
  ans.append(l[i*n+n-1])
print(min(ans))