import heapq
import sys
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)
inf = 1 << 62


class D:
    def __init__(self, dist, now, P) -> None:
        self.dist = dist
        self.now = now
        self.P = P

    def __lt__(self, rhs):
        return self.dist < rhs.dist


def main():
    N, M = map(int, input().split())
    G = [[] for _ in range(N + N)]
    for _ in range(M):
        a, b, c = map(int, input().split())
        a -= 1
        b -= 1
        G[a+N].append((b, c))
        G[b+N].append((a, c))

    T = list(map(int, input().split()))
    for i, t in enumerate(T):
        G[i].append((i+N, t))

    dist = [[inf] * 1001 for _ in range(N + N)]
    dist[0][0] = 0

    pq = [D(0, 0, 0)]    # time, now, eat
    while pq:
        X = heapq.heappop(pq)
        ds = X.dist
        s = X.now
        P = X.P
        if dist[s][P] < ds:
            continue
        for t, dt in G[s]:
            if t == s + N and P + dt <= 1000:
                if dist[t][P + dt] > ds + dt:
                    dist[t][P + dt] = ds + dt
                    heapq.heappush(pq, D(ds + dt, t, P + dt))
            else:
                if dist[t][P] > ds + dt // P:
                    dist[t][P] = ds + dt // P
                    heapq.heappush(pq, D(ds + dt // P, t, P))

    ans = inf
    for i in range(1001):
        ans = min(ans, dist[N-1][i])
    print(ans)


main()