import sys
from heapq import heappop, heappush

input = sys.stdin.buffer.readline


def dijkstra(N, G, s):
    INF = 10 ** 9
    dist = [INF] * N
    que = [(0, s)]
    dist[s] = 0
    while que:
        c, v = heappop(que)
        if dist[v] < c:
            continue
        for t, cost in G[v]:
            if dist[v] + cost < dist[t]:
                dist[t] = dist[v] + cost
                heappush(que, (dist[t], t))
    return dist


N, M = map(int, input().split())
MAX_TIME = 1000
G = [[] for _ in range(N * (MAX_TIME + 1))]


def pair2int(num, time):
    return min(time, MAX_TIME) * N + num


def add_edge(s_num, t_num, s_time, eat_time, length):
    t_time = s_time + eat_time
    if not t_time:
        return
    G[pair2int(s_num, s_time)].append((pair2int(t_num, t_time), eat_time + length // t_time))


edges = []
for _ in range(M):
    a, b, c = map(int, input().split())
    a -= 1
    b -= 1
    edges.append((a, b, c))
T = tuple(map(int, input().split()))
for a, b, c in edges:
    for time in range(MAX_TIME + 1):
        add_edge(a, b, time, T[a], c)
        add_edge(b, a, time, T[b], c)

dist = dijkstra(len(G), G, pair2int(0, 0))
ans = min(dist[pair2int(N - 1, time)] for time in range(MAX_TIME + 1))
print(ans)