from heapq import heapify,heappop,heappush

N,M=map(int,input().split())
E=[[] for _ in range(N)]
for _ in range(M):
    a,b,c=map(int,input().split())
    a-=1; b-=1;

    E[a].append((b,c))
    E[b].append((a,c))

T=list(map(int,input().split()))
T_max=max(T)

inf=float("inf")
D=[[inf]*(T_max*(N-1)+1) for _ in range(N)]

D[0][T[0]]=T[0]
Q=[(T[0],0,T[0])]
heapify(Q)

while Q:
    d,x,t=heappop(Q)

    if x==N-1:
        break

    if D[x][t]<d:
        continue

    for b,c in E[x]:
        k=d+c//t+T[b]
        if k<D[b][t+T[b]]:
            D[b][t+T[b]]=k
            heappush(Q,(k,b,t+T[b]))

print(min(D[-1]))