from heapq import heapify, heappop, heappush
from collections import defaultdict

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

H = [(T[0], 0, T[0])]
heapify(H)
while H:
    t, cp, et = heappop(H)
    if cp == n - 1:
        print(t)
        break
    for np, tt in edge[cp]:
        nt = t + tt // et
        heappush(H, (nt + T[np], np, et + T[np]))