from heapq import heapify, heappop, heappush
N,M = map(int,input().split()); INF = float("inf")
G = [[] for _ in range(N)]
for _ in range(M):
    a,b,c = map(int,input().split())
    a-=1;b-=1
    G[a].append((c,b))
    G[b].append((c,a))
T = list(map(int,input().split()))
MAX = pow(10,3) + 10
#dp[i][j]: i番目の街にいて、おにぎりを計j分食べた時の最小値
dp = [[INF]*MAX for _ in range(N)]
#dp[0][T[0]] = 0

#S:start, V: node, E: Edge, G: Graph
V = len(G)
PQ = []
s = 0
heappush(PQ,(0,s,T[0])) #時間:c,町:v,おにぎり:p
dp[0][T[0]] = T[0]
  
while PQ:
    c,v,p = heappop(PQ) #おにぎりを食べて到着
    #print(c,v,p,dp[v][p])
    #ここで食べる
    #print(c,v,p,dp[v][p])
    #if dp[v][p] < c:
    #    continue
    #dp[v][p] = c
    for dis,u in G[v]:
        np = min(p + T[u], 1001)
        if dp[u][np] <= dis//p + dp[v][p] + T[u]:
            continue
        dp[u][np] = dis//p + dp[v][p] + T[u]
        #print(u,dp[u][np])
        heappush(PQ,(dp[u][np], u, np))
#print(dp)
ans = min(dp[N-1])
print(ans)