import heapq
N,M = map(int,input().split())
G = {i:[] for i in range(1,N+1)}
cmax = 0
for _ in range(M):
    a,b,c = map(int,input().split())
    cmax = max(cmax,c)
    G[a].append((b,c))
    G[b].append((a,c))
T = [0]+list(map(int,input().split()))
F = {(i,j):[] for i in range(1,N+1) for j in range(1,cmax+2)}
for i in range(1,N+1):
    for j in range(1,cmax+2):
        for k,c in G[i]:
            nj = j+T[k]
            if nj>=cmax+1:
                nj = cmax+1
            F[(i,j)].append((k,nj,c))
INFTY = 10**9
dist = [[INFTY for _ in range(cmax+2)] for _ in range(N+1)]
hist = [[0 for _ in range(cmax+2)] for _ in range(N+1)]
dist[1][T[1]] = T[1]
heap = [(T[1],1,T[1])]
while heap:
    d,x,j = heapq.heappop(heap)
    if dist[x][j]<d:continue
    hist[x][j] = 1
    for y,nj,c in F[(x,j)]:
        if dist[y][nj]>d+c//j+T[y] and hist[y][nj]==0:
            dist[y][nj] = d+c//j+T[y]
            heapq.heappush(heap,(dist[y][nj],y,nj))
ans = INFTY
for j in range(1,cmax+2):
    ans = min(ans,dist[N][j])
print(ans)